1
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Zhou P, Ding L, Liu Y, Song H, Wang Q. Iron-Catalyzed Electrophotochemical α-Functionalization of a Silylcyclobutanol. Org Lett 2024; 26:7094-7099. [PMID: 39150853 DOI: 10.1021/acs.orglett.4c02279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2024]
Abstract
Four-membered ring structure is important in organic chemistry, and selective cleavage and functionalization of these strained rings are of great interest. However, direct α-functionalization of cyclobutanols is rarely reported because of the high O-H bond dissociation energy and the occurrence of β-scission of C-C bonds in these alcohols. Recently, transition-metal catalysis has facilitated alkoxy radical generation. Herein, we report a method for electrophotochemical α-functionalization of a silylcyclobutanol via visible-light-induced LMCT reactions of M-alkoxy complexes. Introduction of the silyl group into the cyclobutanol structure favored fast [1,2]-silyl transfer over ring opening, thus allowing the generation of α-functionalized products.
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Affiliation(s)
- Pan Zhou
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Ling Ding
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Yuxiu Liu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Hongjian Song
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Qingmin Wang
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China
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2
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Li S, Tang J, Shi Y, Yan M, Fu Y, Su Z, Xu J, Xue W, Zheng X, Ge Y, Li R, Chen H, Fu H. C3 Selective chalcogenation and fluorination of pyridine using classic Zincke imine intermediates. Nat Commun 2024; 15:7420. [PMID: 39198410 PMCID: PMC11358504 DOI: 10.1038/s41467-024-51452-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 08/08/2024] [Indexed: 09/01/2024] Open
Abstract
Regioselective C-H functionalization of pyridines remains a persistent challenge due to their inherent electronically deficient properties. In this report, we present a strategy for the selective pyridine C3-H thiolation, selenylation, and fluorination under mild conditions via classic N-2,4-dinitrophenyl Zincke imine intermediates. Radical inhibition and trapping experiments, as well as DFT theoretical calculations, indicated that the thiolation and selenylation proceeds through a radical addition-elimination pathway, whereas fluorination via a two-electron electrophilic substitution pathway. The pre-installed electron-deficient activating N-DNP group plays a crucial and positive role, with the additional benefit of recyclability. The practicability of this protocol was demonstrated in the gram-scale synthesis and the late-stage modification of pharmaceutically relevant pyridines.
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Affiliation(s)
- Shun Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Juan Tang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Yonglin Shi
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Meixin Yan
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Yihua Fu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Zhishan Su
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Jiaqi Xu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Weichao Xue
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Xueli Zheng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Yicen Ge
- College of Materials, Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu, Sichuan, 610059, PR China
| | - Ruixiang Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Hua Chen
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China.
| | - Haiyan Fu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China.
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3
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Guo B, Tao Y, Yang T, Su X, Tan X, Tian W, Xie L. Biomaterials based on advanced oxidation processes in tooth whitening: fundamentals, progress, and models. J Mater Chem B 2024. [PMID: 39193628 DOI: 10.1039/d4tb01311e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
The increasing desire for aesthetically pleasing teeth has resulted in the widespread use of tooth whitening treatments. Clinical tooth whitening products currently rely on hydrogen peroxide formulations to degrade dental pigments through oxidative processes. However, they usually cause side effects such as tooth sensitivity and gingival irritation due to the use of high concentrations of hydrogen peroxide or long-time contact. In recent years, various novel materials and reaction patterns have been developed to tackle the issues related to H2O2-based tooth whitening. These can be broadly classified as advanced oxidation processes (AOPs). AOPs generate free radicals that have potent oxidizing properties, which can thereby increase the oxidation power and/or reduce the exposure time and can probably minimize the side effects of tooth bleaching. While there have been several reviews on clinical tooth whitening and the application of novel nanomaterials, a review based on the concept of AOPs in tooth bleaching application has not yet been conducted. This review describes the common types and mechanisms of AOPs, summarizes the latest research progress of new tooth bleaching materials based on AOPs, and proposes a model for tooth bleaching and a rate control step at the molecular level. The paper also reviews the shortcomings and suggests future development directions.
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Affiliation(s)
- Bingyi Guo
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610299, China
| | - Yun Tao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
| | - Tiantian Yang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
| | - Xiaofan Su
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
| | - Xinzhi Tan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
| | - Weidong Tian
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
| | - Li Xie
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Engineering Research Center of Oral Translational Medicine, Ministry of Education & National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
- Rutgers School of Dental Medicine, Newark, New Jersey, USA
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4
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Ngo DT, Garwood JJA, Nagib DA. Cyclopropanation with Non-Stabilized Carbenes via Ketyl Radicals. J Am Chem Soc 2024; 146:24009-24015. [PMID: 39049431 DOI: 10.1021/jacs.4c07388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
A radical mechanism enables simple and robust access to nonstabilized, alkyl iron carbenes for novel (2 + 1) cycloadditions. This Fe-catalyzed strategy employs simple, aliphatic aldehydes as carbene precursors in a practical, efficient, and stereoselective cyclopropanation. This air- and water-tolerant method permits convenient generation of iron carbenes and coupling to an exceptionally wide range of sterically and electronically diverse alkenes (nucleophilic, electrophilic, and neutral). A transient ketyl radical intermediate is key to accessing and harnessing this rare, alkyl iron carbene reactivity. Mechanistic experiments confirm the (a) intermediacy of ketyl radicals, (b) iron carbene formation by radical capture, and (c) nonconcerted nature of the (2 + 1) cycloaddition.
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Affiliation(s)
- Duong T Ngo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Jacob J A Garwood
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - David A Nagib
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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5
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Yan S, Xia D, Zhang T, Liu X. Enhancing oil production via radical reactions during hydrothermal coliquefaction of biomass model compounds and plastics: A molecular dynamic simulation study. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 189:166-176. [PMID: 39197185 DOI: 10.1016/j.wasman.2024.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 08/18/2024] [Accepted: 08/21/2024] [Indexed: 09/01/2024]
Abstract
Recently, hydrothermal coliquefaction of biomass and plastic waste has attracted considerable research interest. However, there is a notable gap in understanding the fundamental reaction mechanisms between biomass and plastics during coliquefaction. This study focused on the coliquefaction of biomass model compounds and plastic polymers using ReaxFF molecular dynamics simulations under both subcritical and supercritical water conditions. Molecular-level tracking and probing of the reaction mechanisms between biomass model compounds and plastics were conducted to purposefully enhance oil production. The study observed related radical reactions between by-product molecules, with detailed mechanisms primarily involving (1) ▪OH radicals released by aqueous phase molecules from biomolecules, transferring as H2O molecules and facilitating plastic depolymerization, and (2) C1-C4 radicals in the gaseous phase, emitted from biomolecule and plastic, colliding and subsequently recombining to form oil molecules. Moreover, the yield of multiple products from various mixtures were evaluated by considering the key reaction parameters including reaction temperature and feedstock blended ratio. An exploration into the effect of coliquefaction on oil yield was conducted to precisely identify the optimal coliquefaction conditions. The positive effect of coliquefaction was more pronounced between biomass model compounds and aromatic polymers compared to aliphatic polymers. Analysis of reaction mechanisms and product outcomes has shown that hydrothermal coliquefaction is a viable approach to improving oil production from multi-source organic solid waste.
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Affiliation(s)
- Shuo Yan
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Dehong Xia
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory for Energy Saving and Emission Reduction of Metallurgical Industry, Beijing 100083, China.
| | - Tongtong Zhang
- School of Chemical Engineering & Birmingham Centre for Energy Storage, University of Birmingham, Birmingham B15 2TT, UK
| | - Xiangjun Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
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6
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Zhou X, Xu W, Wang B, Iqbal A, Chen Z, Xia Y, Jin W, Liu C, Zhang Y. Photo-Driven Regiodivergent Arylation/Cyclization and Arylation/Hydroxylation of N-Aryl Methacrylamides with Aryltriazenes: Access to Functionalized 3,3-Disubstituted Oxindoles and α-Hydroxylamides. J Org Chem 2024. [PMID: 39167091 DOI: 10.1021/acs.joc.4c01492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
A metal-free, light-induced regiodivergent functionalization of α,β-unsaturated amides with aryltriazenes under ambient conditions was developed. The visible light and B(C6F5)3 cocatalyzed radical cascade arylation/cyclization of N-alkyl-N-arylmethacrylamides can obtain functionalized 3,3-disubstituted oxindoles with the assistance of photocatalyst eosin Y-Na2. In the absence of any catalyst, with purple light irradiation and electron-donor-acceptor (EDA) complex initiation, the radical cascade arylation/hydroxylation of N-arylmethacrylamides affords α-hydroxylamides. This methodology highlights the arts in accessing different regioisomers by altering the substrates and photocatalytic strategies.
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Affiliation(s)
- Xinlei Zhou
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Wei Xu
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Bin Wang
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Azhar Iqbal
- Department of Chemistry, Bacha Khan University, Charsadda 24420, Pakistan
| | - Ziren Chen
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Yu Xia
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Weiwei Jin
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Chenjiang Liu
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
| | - Yonghong Zhang
- Urumqi Key Laboratory of Green Catalysis and Synthesis Technology, Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China
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7
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Yamada Y, Yoshinaga R, Matsui Y, Nagatomo M, Fujino H, Inoue M. Et 3Al/Light-Promoted Radical-Polar Crossover Reactions of α-Alkoxyacyl Tellurides. J Org Chem 2024; 89:11701-11706. [PMID: 39110480 DOI: 10.1021/acs.joc.4c01445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Here, we report new radical-polar crossover reactions of α-alkoxy carbon radicals for constructing highly oxygenated molecules with contiguous stereocenters. The method employs a 370 nm UV light-emitting diode (LED) for the photoexcitation of α-alkoxyacyl telluride, and Et3Al as the radical initiator and terminator. First, Et3Al and UV LED promoted radical coupling between the α-alkoxyacyl telluride and cyclopentenone via C-Te bond homolysis, CO expulsion, and C-C bond formation. Second, Et3Al converted the radical species to the corresponding aluminum enolate. Third, the second C-C bond formation occurred via a polar mechanism: intermolecularly with aldehydes/ketones and intramolecularly with epoxide, producing aldol and SN2 adducts, respectively. The present coupling reactions increase the molecular complexity in a single step by stereoselective formation of the two hindered C-C bonds. The devised method is expected to be useful for the expeditious assembly of densely oxygenated natural products.
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Affiliation(s)
- Yutaro Yamada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Risa Yoshinaga
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yuki Matsui
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Haruka Fujino
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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8
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Huang M, Sun H, Seufert F, Friedrich A, Marder TB, Hu J. Photoredox/Cu-Catalyzed Decarboxylative C(sp 3)-C(sp 3) Coupling to Access C(sp 3)-Rich gem-Diborylalkanes. Angew Chem Int Ed Engl 2024; 63:e202401782. [PMID: 38818649 DOI: 10.1002/anie.202401782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/28/2024] [Accepted: 05/28/2024] [Indexed: 06/01/2024]
Abstract
gem-Diborylalkanes are highly valuable building blocks in organic synthesis and pharmaceutical chemistry due to their ability to participate in multi-step cross-coupling transformations, allowing for the rapid generation of molecular complexity. While progress has been made in their synthetic metholodology, the construction of β-tertiary and C(sp3)-rich gem-diborylalkanes remains a synthetic challenge due to substrate limitations and steric hindrance issues. An approach is presented that utilizes synergistic photoredox and copper catalysis to achieve efficient C(sp3)-C(sp3) cross-coupling of alkyl N-hydroxyphthalimide esters, which can easily be obtained from alkyl carboxylic acids, with diborylmethyl species, providing a series of C(sp3)-rich gem-diborylalkanes with 1°, 2°, and even 3° β positions. Furthermore, this approach can also be applied to complex medicinal compounds and natural products, offering rapid access to molecular complexity and late-stage functionalization of C(sp3)-rich drug candidates. Mechanistic experiments revealed that diborylmethyl Cu(I) species participated in both the photoredox process and the key C(sp3)-C(sp3) bond-forming step.
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Affiliation(s)
- Mingming Huang
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Huaxing Sun
- State Key Laboratory of Organic Electronics and Information Displays & & Institute of Advanced Materials (IAM), College of Chemistry and Life Sciences, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Florian Seufert
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexandra Friedrich
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Todd B Marder
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jiefeng Hu
- State Key Laboratory of Organic Electronics and Information Displays & & Institute of Advanced Materials (IAM), College of Chemistry and Life Sciences, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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9
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Holovach S, Poroshyn I, Melnykov KP, Liashuk OS, Pariiska OO, Kolotilov SV, Rozhenko AB, Volochnyuk DM, Grygorenko OO. Parallel Minisci Reaction of gem-Difluorocycloalkyl Building Blocks. ACS ORGANIC & INORGANIC AU 2024; 4:424-431. [PMID: 39132014 PMCID: PMC11311045 DOI: 10.1021/acsorginorgau.4c00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 08/13/2024]
Abstract
Parallel Minisci reactions of nonfluorinated and gem-difluorinated C4-C7 cycloalkyl building blocks (trifluoroborates and carboxylic acids) with a series of electron-deficient heterocycles were studied. A comparison of the reaction's outcome revealed better product yields in the case of carboxylic acids as the radical precursors in most cases, albeit these reagents were used with three-fold excess under optimized conditions. The nature of the heterocyclic core was found to be important for successful incorporation of the cycloalkyl fragment. The impact of the CF2 moiety on the oxidation potential of fluorinated cycloalkyl trifluoroborates and the reaction outcome, in general, was also evaluated.
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Affiliation(s)
- Serhii Holovach
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- Institute
of Organic Chemistry of National Academy of Sciences of Ukraine, Akademik Kukhar Street 5, Kyïv 02066, Ukraine
| | - Illia Poroshyn
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- Taras
Shevchenko National University of Kyiv, Volodymyrska Street 60, Kyïv 01601, Ukraine
| | - Kostiantyn P. Melnykov
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- Taras
Shevchenko National University of Kyiv, Volodymyrska Street 60, Kyïv 01601, Ukraine
| | - Oleksandr S. Liashuk
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- Taras
Shevchenko National University of Kyiv, Volodymyrska Street 60, Kyïv 01601, Ukraine
| | - Olena O. Pariiska
- L.
V. Pisarzhevskii Institute of Physical Chemistry of National Academy
of Sciences of Ukraine, Nauky Avenue 31, Kyïv 03028, Ukraine
| | - Sergey V. Kolotilov
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- L.
V. Pisarzhevskii Institute of Physical Chemistry of National Academy
of Sciences of Ukraine, Nauky Avenue 31, Kyïv 03028, Ukraine
| | - Alexander B. Rozhenko
- Institute
of Organic Chemistry of National Academy of Sciences of Ukraine, Akademik Kukhar Street 5, Kyïv 02066, Ukraine
- Taras
Shevchenko National University of Kyiv, Volodymyrska Street 60, Kyïv 01601, Ukraine
| | - Dmytro M. Volochnyuk
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- Institute
of Organic Chemistry of National Academy of Sciences of Ukraine, Akademik Kukhar Street 5, Kyïv 02066, Ukraine
- Taras
Shevchenko National University of Kyiv, Volodymyrska Street 60, Kyïv 01601, Ukraine
| | - Oleksandr O. Grygorenko
- Enamine
Ltd., Winston Churchill Street 78, Kyïv 02094, Ukraine
- Institute
of Organic Chemistry of National Academy of Sciences of Ukraine, Akademik Kukhar Street 5, Kyïv 02066, Ukraine
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10
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Xu S, Wang Q, Rajeshkumar T, Jiang S, Maron L, Xu X. Reductive Dimerization of Alkenes and Allenes Enabled by Photochemically Activated Zinc-Zinc Bonded Compounds. J Am Chem Soc 2024; 146:19590-19598. [PMID: 38957130 DOI: 10.1021/jacs.4c07390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Metal radicals have shown versatile reactivity in modern synthetic chemistry. However, the use of zinc radicals for molecular synthesis has been barely explored. Here, we show that a transient zinc radical can be formed through photoactivation of a zinc-zinc bonded compound, which is able to mediate the selective dimerization of alkenes and allenes. Treatment of dizinc compounds [L2Zn2] [L = CH3C(2,6-iPr2C6H3N)CHC(CH3)(NCH2CH2PR2); R = Ph (LPh) or iPr (LiPr)] with a diverse array of aromatic alkenes under UV irradiation (365 nm) facilely afforded the head-to-head coupling products, i.e., 1,4-dizinciobutanes in high yields. In addition, arylallenes could also be selectively dimerized by the dizinc compound to give 2,5-dizincyl-functionalized 1,5-hexadienes under the same conditions. Control reactions of [LPh2Zn2] in the presence of UV irradiation isolated a zinc phenyl complex and a trimeric zinc phosphide complex resulting from C-P bond cleavage at the tridentate ligand. Reactions of photoactivated dizinc compounds with organic spin traps, i.e., 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and 2,2'-bipyridine (2,2'-bpy), successfully isolated zinc radical trapping products [LZnOTEMP] and [LPhZn(2,2'-bpy)·-], respectively. The profile of alkene dimerization was elucidated by density functional theory calculations, which confirmed that a transient zinc radical [LZn·] was initially generated through homolytic Zn-Zn bond cleavage via photoactivation followed by single-electron transfer and radical dimerization. The unique selectivity of the current reaction was also studied computationally.
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Affiliation(s)
- Shuilian Xu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Qiujie Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Thayalan Rajeshkumar
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, Toulouse 31077, France
| | - Shengjie Jiang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Laurent Maron
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, Toulouse 31077, France
| | - Xin Xu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
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11
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Nishikata T. α-Halocarbonyls as a Valuable Functionalized Tertiary Alkyl Source. ChemistryOpen 2024:e202400108. [PMID: 38989712 DOI: 10.1002/open.202400108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/21/2024] [Indexed: 07/12/2024] Open
Abstract
This review introduces the synthetic organic chemical value of α-bromocarbonyl compounds with tertiary carbons. This α-bromocarbonyl compound with a tertiary carbon has been used primarily only as a radical initiator in atom transfer radical polymerization (ATRP) reactions. However, with the recent development of photo-radical reactions (around 2010), research on the use of α-bromocarbonyl compounds as tertiary alkyl radical precursors became popular (around 2012). As more examples were reported, α-bromocarbonyl compounds were studied not only as radicals but also for their applications in organometallic and ionic reactions. That is, α-bromocarbonyl compounds act as nucleophiles as well as electrophiles. The carbonyl group of α-bromocarbonyl compounds is also attractive because it allows the skeleton to be converted after the reaction, and it is being applied to total synthesis. In our survey until 2022, α-bromocarbonyl compounds can be used to perform a full range of reactions necessary for organic synthesis, including multi-component reactions, cross-coupling, substitution, cyclization, rearrangement, stereospecific reactions, asymmetric reactions. α-Bromocarbonyl compounds have created a new trend in tertiary alkylation, which until then had limited reaction patterns in organic synthesis. This review focuses on how α-bromocarbonyl compounds can be used in synthetic organic chemistry.
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Affiliation(s)
- Takashi Nishikata
- Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi, 755-8611, Japan
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12
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Liu H, Li W, Xu X, Yang M, Han D, Yang X. Visible light driven photoredox/nickel-catalyzed stereoselective synthesis of Z- or E-vinyl thioethers from thiosilane and terminal alkynes. Org Biomol Chem 2024; 22:5524-5528. [PMID: 38899407 DOI: 10.1039/d4ob00652f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
A new method for the synthesis of anti-Markovnikov Z- or E-vinyl thioethers from thiosilane and terminal alkynes under visible-light-induced photoredox/nickel dual catalysis conditions is described. With a judicious choice of a simple nickel catalyst and a ligand, this strategy enables efficient and divergent access to both Z- or E-vinyl thioethers from the same set of simple starting materials. Notably, the approach is free of odorous thiol and has excellent compatibility with functional groups and substrate scope.
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Affiliation(s)
- Hongqiang Liu
- School of Pharmaceutical, Chemical and Materials Engineering, Taizhou University, Taizhou, 318000, China.
| | - Wenjing Li
- School of Pharmaceutical, Chemical and Materials Engineering, Taizhou University, Taizhou, 318000, China.
| | - Xia Xu
- School of Pharmaceutical, Chemical and Materials Engineering, Taizhou University, Taizhou, 318000, China.
| | - Meiding Yang
- School of Pharmaceutical, Chemical and Materials Engineering, Taizhou University, Taizhou, 318000, China.
| | - Deman Han
- School of Pharmaceutical, Chemical and Materials Engineering, Taizhou University, Taizhou, 318000, China.
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13
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Zheng Y, Dong QX, Wen SY, Ran H, Huang HM. Di-π-ethane Rearrangement of Cyano Groups via Energy-Transfer Catalysis. J Am Chem Soc 2024; 146:18210-18217. [PMID: 38788197 DOI: 10.1021/jacs.4c04370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
Molecular rearrangement occupies a pivotal position among fundamental transformations in synthetic chemistry. Radical translocation has emerged as a prevalent synthetic tool, efficiently facilitating the migration of diverse functional groups. In contrast, the development of di-π-methane rearrangement remains limited, particularly in terms of the translocation of cyano functional groups. This is primarily attributed to the energetically unfavorable three-membered-ring transition state. Herein, we introduce an unprecedented di-π-ethane rearrangement enabled by energy-transfer catalysis under visible light conditions. This innovative open-shell rearrangement boasts broad tolerance toward a range of functional groups, encompassing even complex drug and natural product derivatives. Overall, the reported di-π-ethane rearrangement represents a complementary strategy to the development of radical translocation enabled by energy-transfer catalysis.
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Affiliation(s)
- Yu Zheng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qi-Xin Dong
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shu-Ya Wen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Hui Ran
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Huan-Ming Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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14
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Jiang C, Hu L, Shen S, Zhang J, Wang X, Ma D, Lu G, Xu T. Type I [4σ+4π] versus [4σ+4π-1] Cycloaddition To Access Medium-Sized Carbocycles and Discovery of a Liver X Receptor β-Selective Ligand. Angew Chem Int Ed Engl 2024; 63:e202405838. [PMID: 38647574 DOI: 10.1002/anie.202405838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 04/12/2024] [Accepted: 04/22/2024] [Indexed: 04/25/2024]
Abstract
Transition-metal-catalyzed [4+4] cycloaddition leading to cyclooctanoids has centered on dimerization between 1,3-diene-type substrates. Herein, we describe a [4σ+4π-1] and [4σ+4π] cycloaddition strategy to access 7/8-membered fused carbocycles through rhodium-catalyzed coupling between the 4σ-donor (benzocyclobutenones) and pendant diene (4π) motifs. The two pathways can be controlled by adjusting the solvated CO concentration. A broad range (>40 examples) of 5-6-7 and 5-6-8 polyfused carbocycles was obtained in good yields (up to 90 %). DFT calculations, kinetic monitoring and 13C-labeling experiments were carried out, suggesting a plausible mechanism. Notably, one 5-6-7 tricycle was found to be a very rare, potent, and selective ligand for the liver X receptor β (KD=0.64 μM), which is a potential therapeutic target for cholesterol-metabolism-related fatal diseases.
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Affiliation(s)
- Cheng Jiang
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education; School of Medicine and Pharmacy, Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Ocean University of China, 5 Yushan road, Qingdao, 266003, China
| | - Lingfei Hu
- School of Chemistry and Chemical Engineering, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, 27 Shandanan road, Jinan, 250100, China
| | - Shuna Shen
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education; School of Medicine and Pharmacy, Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Ocean University of China, 5 Yushan road, Qingdao, 266003, China
| | - Jianyu Zhang
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education; School of Medicine and Pharmacy, Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Ocean University of China, 5 Yushan road, Qingdao, 266003, China
| | - Xi Wang
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education; School of Medicine and Pharmacy, Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Ocean University of China, 5 Yushan road, Qingdao, 266003, China
| | - Dongxu Ma
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education; School of Medicine and Pharmacy, Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Ocean University of China, 5 Yushan road, Qingdao, 266003, China
| | - Gang Lu
- School of Chemistry and Chemical Engineering, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, 27 Shandanan road, Jinan, 250100, China
| | - Tao Xu
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education; School of Medicine and Pharmacy, Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Ocean University of China, 5 Yushan road, Qingdao, 266003, China
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15
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Liu ZR, Zhu XY, Guo JF, Ma C, Zuo Z, Mei TS. Synergistic use of photocatalysis and convergent paired electrolysis for nickel-catalyzed arylation of cyclic alcohols. Sci Bull (Beijing) 2024; 69:1866-1874. [PMID: 38670850 DOI: 10.1016/j.scib.2024.04.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/25/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024]
Abstract
The merging of transition metal catalysis with electrochemistry has become a powerful tool for organic synthesis because catalysts can govern the reactivity and selectivity. However, coupling catalysts with alkyl radical species generated by anodic oxidation remains challenging because of electrode passivation, dimerization, and overoxidation. In this study, we developed convergent paired electrolysis for the coupling of nickel catalysts with alkyl radicals derived from photoinduced ligand-to-metal charge-transfer of cyclic alcohols and iron catalysts, providing a practical method for site-specific and remote arylation of ketones. The synergistic use of photocatalysis with convergent paired electrolysis can provide alternative avenues for metal-catalyzed radical coupling reactions.
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Affiliation(s)
- Zhao-Ran Liu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Xiao-Yu Zhu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jian-Feng Guo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Cong Ma
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Tian-Sheng Mei
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
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16
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Hanumanthu R, Weaver JD. Cooperative Catalytic Coupling of Benzyl Chlorides and Bromides with Electron-Deficient Alkenes. Org Lett 2024; 26:5248-5252. [PMID: 38896786 PMCID: PMC11217938 DOI: 10.1021/acs.orglett.4c01413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/07/2024] [Accepted: 06/13/2024] [Indexed: 06/21/2024]
Abstract
Benzyl radicals are an important class of intermediate. The use of visible light to generate them directly from their respective halides is an ideal synthetic strategy. The central impediment associated with their direct single-electron reduction (photo- or electro-) lies in their highly variable and structurally dependent reduction potential, which combine to make the identification of a general set of conditions difficult. Herein, we have employed a strategy of nucleophilic cooperative catalysis in which catalytic lutidine undergoes halide substitution, which decreases and levels the reduction potential. This allows a general set of photocatalytic conditions to transform a broad range of benzyl halides into radicals that can be used in the synthesis of more complex molecules, exemplified here by Giese coupling with electron-deficient alkenes.
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Affiliation(s)
- Roshini Hanumanthu
- 107 Physical Science, Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Jimmie D. Weaver
- 107 Physical Science, Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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17
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Mohamadpour F, Amani AM. Photocatalytic systems: reactions, mechanism, and applications. RSC Adv 2024; 14:20609-20645. [PMID: 38952944 PMCID: PMC11215501 DOI: 10.1039/d4ra03259d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 06/21/2024] [Indexed: 07/03/2024] Open
Abstract
The photocatalytic field revolves around the utilization of photon energy to initiate various chemical reactions using non-adsorbing substrates, through processes such as single electron transfer, energy transfer, or atom transfer. The efficiency of this field depends on the capacity of a light-absorbing metal complex, organic molecule, or substance (commonly referred to as photocatalysts or PCs) to execute these processes. Photoredox techniques utilize photocatalysts, which possess the essential characteristic of functioning as both an oxidizing and a reducing agent upon activation. In addition, it is commonly observed that photocatalysts exhibit optimal performance when irradiated with low-energy light sources, while still retaining their catalytic activity under ambient temperatures. The implementation of photoredox catalysis has resuscitated an array of synthesis realms, including but not limited to radical chemistry and photochemistry, ultimately affording prospects for the development of the reactions. Also, photoredox catalysis is utilized to resolve numerous challenges encountered in medicinal chemistry, as well as natural product synthesis. Moreover, its applications extend across diverse domains encompassing organic chemistry and catalysis. The significance of photoredox catalysts is rooted in their utilization across various fields, including biomedicine, environmental pollution management, and water purification. Of course, recently, research has evaluated photocatalysts in terms of cost, recyclability, and pollution of some photocatalysts and dyes from an environmental point of view. According to these new studies, there is a need for critical studies and reviews on photocatalysts and photocatalytic processes to provide a solution to reduce these limitations. As a future perspective for research on photocatalysts, it is necessary to put the goals of researchers on studies to overcome the limitations of the application and efficiency of photocatalysts to promote their use on a large scale for the development of industrial activities. Given the significant implications of the subject matter, this review seeks to delve into the fundamental tenets of the photocatalyst domain and its associated practical use cases. This review endeavors to demonstrate the prospective of a powerful tool known as photochemical catalysis and elucidate its underlying tenets. Additionally, another goal of this review is to expound upon the various applications of photocatalysts.
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Affiliation(s)
- Farzaneh Mohamadpour
- Department of Medical Nanotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences Shiraz Iran
| | - Ali Mohammad Amani
- Department of Medical Nanotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences Shiraz Iran
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18
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Jain S, Ospina F, Hammer SC. A New Age of Biocatalysis Enabled by Generic Activation Modes. JACS AU 2024; 4:2068-2080. [PMID: 38938808 PMCID: PMC11200230 DOI: 10.1021/jacsau.4c00247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 06/29/2024]
Abstract
Biocatalysis is currently undergoing a profound transformation. The field moves from relying on nature's chemical logic to a discipline that exploits generic activation modes, allowing for novel biocatalytic reactions and, in many instances, entirely new chemistry. Generic activation modes enable a wide range of reaction types and played a pivotal role in advancing the fields of organo- and photocatalysis. This perspective aims to summarize the principal activation modes harnessed in enzymes to develop new biocatalysts. Although extensively researched in the past, the highlighted activation modes, when applied within enzyme active sites, facilitate chemical transformations that have largely eluded efficient and selective catalysis. This advance is attributed to multiple tunable interactions in the substrate binding pocket that precisely control competing reaction pathways and transition states. We will highlight cases of new synthetic methodologies achieved by engineered enzymes and will provide insights into potential future developments in this rapidly evolving field.
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Affiliation(s)
| | | | - Stephan C. Hammer
- Research Group for Organic Chemistry
and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
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19
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Zhang T, Rabeah J, Das S. Red-light-mediated copper-catalyzed photoredox catalysis promotes regioselectivity switch in the difunctionalization of alkenes. Nat Commun 2024; 15:5208. [PMID: 38890327 PMCID: PMC11189478 DOI: 10.1038/s41467-024-49514-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 06/05/2024] [Indexed: 06/20/2024] Open
Abstract
Controlling regioselectivity during difunctionalization of alkenes remains a significant challenge, particularly when the installation of both functional groups involves radical processes. In this aspect, methodologies to install trifluoromethane (-CF3) via difunctionalization have been explored, due to the importance of this moiety in the pharmaceutical sectors; however, these existing reports are limited, most of which affording only the corresponding β-trifluoromethylated products. The main reason for this limitation arises from the fact that -CF3 group served as an initiator in those reactions and predominantly preferred to be installed at the terminal (β) position of an alkene. On the contrary, functionalization of the -CF3 group at the internal (α) position of alkenes would provide valuable products, but a meticulous approach is necessary to win this regioselectivity switch. Intrigued by this challenge, we here develop an efficient and regioselective strategy where the -CF3 group is installed at the α-position of an alkene. Molecular complexity is achieved via the simultaneous insertion of a sulfonyl fragment (-SO2R) at the β-position. A precisely regulated sequence of radical generation using red light-mediated photocatalysis facilitates this regioselective switch from the terminal (β) position to the internal (α) position. Furthermore, this approach demonstrates broad substrate scope and industrial potential for the synthesis of pharmaceuticals under mild reaction conditions.
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Affiliation(s)
- Tong Zhang
- Department of Chemistry, University of Antwerp, Antwerp, Belgium
| | - Jabor Rabeah
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Rostock, Germany
- State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, P. R. China
| | - Shoubhik Das
- Department of Chemistry, University of Antwerp, Antwerp, Belgium.
- Department of Chemistry, University of Bayreuth, Bayreuth, Germany.
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20
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Gu X, Li Z, Su J. Air pollution and skin diseases: A comprehensive evaluation of the associated mechanism. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 278:116429. [PMID: 38718731 DOI: 10.1016/j.ecoenv.2024.116429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/28/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024]
Abstract
Air pollutants deteriorate the survival environment and endanger human health around the world. A large number of studies have confirmed that air pollution jeopardizes multiple organs, such as the cardiovascular, respiratory, and central nervous systems. Skin is the largest organ and the first barrier that protects us from the outside world. Air pollutants such as particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) will affect the structure and function of the skin and bring about the development of inflammatory skin diseases (atopic dermatitis (AD), psoriasis), skin accessory diseases (acne, alopecia), auto-immune skin diseases (cutaneous lupus erythematosus(CLE) scleroderma), and even skin tumors (melanoma, basal cell carcinoma (BCC), squamous-cell carcinoma (SCC)). Oxidative stress, skin barrier damage, microbiome dysbiosis, and skin inflammation are the pathogenesis of air pollution stimulation. In this review, we summarize the current evidence on the effects of air pollution on skin diseases and possible mechanisms to provide strategies for future research.
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Affiliation(s)
- Xiaoyu Gu
- Department of Dermatology | Hunan Engineering Research Center of Skin Health and Disease | Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Central South University, Changsha 410008, China; National Engineering Research Center of Personalized Diagnostic and Therapeutic Technology, Changsha 410008, China; National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha 410008, China; Furong Laboratory, Changsha, Hunan 410008, China
| | - Zhengrui Li
- XiangYa School of Medicine, Central South University, Changsha 410008, China
| | - Juan Su
- Department of Dermatology | Hunan Engineering Research Center of Skin Health and Disease | Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Central South University, Changsha 410008, China; National Engineering Research Center of Personalized Diagnostic and Therapeutic Technology, Changsha 410008, China; National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha 410008, China; Furong Laboratory, Changsha, Hunan 410008, China.
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21
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Li Y, Sun L, Huang S, Xu K, Zeng CC. Electrochemical quinuclidine-mediated Minisci-type acylation of N-heterocycles with aldehydes. Chem Commun (Camb) 2024; 60:6174-6177. [PMID: 38804811 DOI: 10.1039/d4cc00800f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The electro-generation of acyl radicals from both aromatic and aliphatic aldehydes remains an unmet challenge. We provide a solution to this challenge by merging electro-oxidation and a quinuclidine-mediated hydrogen atom transfer strategy. The generation of acyl radicals at decreased applied potentials compared to that of formyl oxidation exhibits excellent functional group compatibility.
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Affiliation(s)
- Yongmei Li
- College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China.
| | - Liangbo Sun
- College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China.
| | - Shengyang Huang
- College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China.
| | - Kun Xu
- College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China.
| | - Cheng-Chu Zeng
- College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China.
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22
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Grunshaw T, Wood SH, Sproules S, Parrott A, Nordon A, Shapland PDP, Wheelhouse KMP, Tomkinson NCO. A Mechanistic Investigation of the N-Hydroxyphthalimide Catalyzed Benzylic Oxidation Mediated by Sodium Chlorite. J Org Chem 2024; 89:7933-7945. [PMID: 38748510 PMCID: PMC11165572 DOI: 10.1021/acs.joc.4c00583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 06/13/2024]
Abstract
A detailed investigation into the mechanistic course of N-hydroxyphthalimide catalyzed oxidation of benzylic centers using sodium chlorite as the stoichiometric oxidant is reported. Through a combination of experimental, spectroscopic, and computational techniques, the transformation is interrogated, providing improved reaction conditions and an enhanced understanding of the mechanism. Performing the transformation in the presence of acetic acid or a pH 4.5 buffer leads to extended reaction times but improves the catalyst lifetime, leading to the complete consumption of the starting material. Chlorine dioxide is identified as the active oxidant that is able to oxidize the N-hydroxyphthalimide anion to the phthalimide-N-oxyl radical, the proposed catalytically active species, which is able to abstract a hydrogen atom from the substrate. A second molecule of chlorine dioxide reacts with the resultant radical and, after loss of hypochlorous acid, leads to the observed product. Through a broad variety of techniques including UV/vis, EPR and Raman spectroscopy, isotopic labeling, and the use of radical traps, evidence for the mechanism is presented that is supported through electronic structural calculations.
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Affiliation(s)
- Thomas Grunshaw
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
- GlaxoSmithKline
R&D, Gunnels Wood
Road, Stevenage SG1 2NY, U.K.
| | - Susanna H. Wood
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Stephen Sproules
- School
of Chemistry, University of Glasgow, Glasgow G12 8QQ, U.K.
| | - Andrew Parrott
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Alison Nordon
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
| | | | | | - Nicholas C. O. Tomkinson
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
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23
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Kachore A, Aggarwal V, Bala E, Singh H, Guleria S, Sharma S, Pathan S, Saima, Selvaraj M, Assiri MA, Kumar Verma P. Recent Advances in Direct Regioselective C-H Chlorination at Aromatic and Aliphatic. Chem Asian J 2024:e202400391. [PMID: 38825568 DOI: 10.1002/asia.202400391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/31/2024] [Accepted: 05/31/2024] [Indexed: 06/04/2024]
Abstract
Direct installation of key functionalities in a molecule through C-H bond activation is one of the thrust areas as well as challenging task in organic synthesis. Particularly, introduction of chlorine in a molecule imparts additional benefits for further functionalizations as well as improves the electronic behaviour such as lipophilicity and polarity towards drug development process. The chlorinated molecules have also been established as efficient biologically relevant scaffolds. Current manuscript has been focused on the direct installation of the chlorine atom at various aromatic and aliphatic positions to produce functional molecules. The key highlight of the manuscript belongs to the site selectivity (regioselectivity) for the installation of chlorine functionality. Manuscript describes the advanced methods developed for the direct C-H chlorination reactions and further simplified for the chlorination reactions at various positions including aromatic (o-, m-, and p-), benzylic, heteroaromatic, and aliphatic positions. Directing groups (DGs) and the coordination with the catalyst is the key for the enhancement of regioselectivities during direct C-H chlorination reactions.
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Affiliation(s)
- Ankit Kachore
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Varun Aggarwal
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Ekta Bala
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Hemant Singh
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Saksham Guleria
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Sakshi Sharma
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Sameer Pathan
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Saima
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Manickam Selvaraj
- Department of Chemistry, Faculty of Science, King Khalid University, PO Box 9004, 61413, Abha, Saudi Arabia
- Research Centre for Advanced Materials Science (RCAMS), King Khalid University, PO Box 9004, Abha, 61413, Saudi Arabia
| | - Mohammed A Assiri
- Department of Chemistry, Faculty of Science, King Khalid University, PO Box 9004, 61413, Abha, Saudi Arabia
- Research Centre for Advanced Materials Science (RCAMS), King Khalid University, PO Box 9004, Abha, 61413, Saudi Arabia
| | - Praveen Kumar Verma
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
- Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospitals, SIMATS, Saveetha University, 600077, Chennai, Tamil Nadu, India
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24
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Piedra HF, Plaza M. Advancements in visible-light-induced reactions via alkenyl radical intermediates. Photochem Photobiol Sci 2024; 23:1217-1228. [PMID: 38700648 DOI: 10.1007/s43630-024-00580-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 04/15/2024] [Indexed: 06/18/2024]
Abstract
In recent years, visible-light-induced organic transformations have taken a central role driving forward the progress of modern organic synthesis. These processes typically involve the transient generation of highly reactive radical intermediates, facilitating a diverse array of chemical reactions. Despite the abundance of synthetic strategies enabling the access of aryl and alkyl-centered radicals, the exploitation of photochemistry to generate highly reactive alkenyl radicals has remained notably underdeveloped. In this review, we present recent advancements in visible-light-induced transformations that proceed through the generation of alkenyl radicals from alkenyl-containing precursors, predominantly alkenyl halides, showcasing their application in various organic transformations.
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Affiliation(s)
- Helena F Piedra
- Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles" and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Oviedo, Julián Clavería, 8, 33006, Oviedo, Spain
| | - Manuel Plaza
- Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles" and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Oviedo, Julián Clavería, 8, 33006, Oviedo, Spain.
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25
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Budny-Godlewski K, Piekarski DG, Justyniak I, Leszczyński MK, Nawrocki J, Kubas A, Lewiński J. Uncovering Factors Controlling Reactivity of Metal-TEMPO Reaction Systems in the Solid State and Solution. Chemistry 2024:e202401968. [PMID: 38801170 DOI: 10.1002/chem.202401968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Nitroxides find application in various areas of chemistry, and a more in-depth understanding of factors controlling their reactivity with metal complexes is warranted to promote further developments. Here, we report on the effect of the metal centre Lewis acidity on both the distribution of the O- and N-centered spin density in 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and turning TEMPO from the O- to N-radical mode scavenger in metal-TEMPO systems. We use Et(Cl)Zn/TEMPO model reaction system with tuneable reactivity in the solid state and solution. Among various products, a unique Lewis acid-base adduct of Cl2Zn with the N-ethylated TEMPO was isolated and structurally characterised, and the so-called solid-state 'slow chemistry' reaction led to a higher yield of the N-alkylated product. The revealed structure-activity/selectivity correlations are exceptional yet are entirely rationalised by the mechanistic underpinning supported by theoretical calculations of studied model systems. This work lays a foundation and mechanistic blueprint for future metal/nitroxide systems exploration.
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Affiliation(s)
- Krzysztof Budny-Godlewski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Dariusz G Piekarski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Iwona Justyniak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Michał K Leszczyński
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Jan Nawrocki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Adam Kubas
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Janusz Lewiński
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
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26
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Chen C, Chen YX, Zhang CJ. A Radical-Generating Probe to Release Free Fluorophores and Identify Artemisinin-Sensitive Cancer Cells. ACS Sens 2024; 9:2310-2316. [PMID: 38651676 DOI: 10.1021/acssensors.4c00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
The smart light-up probes have been extensively developed to image various enzymes and other bioactive molecules. Upon activation, these probes result in light-up fluorophores that exist in a protein-bound or a free form. The difference between these two forms has not yet been reported. Here, we present a pair of smart light-up probes that generate a protein-bound fluorophore and a free fluorophore upon activation by heme. Probe 8 generated a radical-attached fluorophore that predominantly existed in the free form, while probe 10 generated an α,β-unsaturated ketone-attached fluorophore that showed extensive labeling of proteins. In live-cell imaging, probe 8 showed greater fluorescence intensity than probe 10 when low concentrations (0.1-5 μM) of the probes were used, but probe 8 was less fluorescent than probe 10 when the concentrations of the probes were high (10 μM). Finally, probe 8 was used to reflect the activation level of the endoperoxide bond in cancer cells and to effectively distinguish ART-sensitive cancer cells from ART-insensitive ones.
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Affiliation(s)
- Chen Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yi-Xin Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Chong-Jing Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
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27
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Chen Y, Xu S, Fang Wen C, Zhang H, Zhang T, Lv F, Yue Y, Bian Z. Unravelling the Role of Free Radicals in Photocatalysis. Chemistry 2024; 30:e202400001. [PMID: 38501217 DOI: 10.1002/chem.202400001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 03/20/2024]
Abstract
Free radicals are increasingly recognized as active intermediate reactive species that can participate in various redox processes, significantly influencing the mechanistic pathways of reactions. Numerous researchers have investigated the generation of one or more distinct photogenerated radicals, proposing various hypotheses to explain the reaction mechanisms. Notably, recent research has demonstrated the emergence of photogenerated radicals in innovative processes, including organic chemical reactions and the photocatalytic dissolution of precious metals. To harness the potential of these free radicals more effectively, it is imperative to consolidate and analyze the processes and action modes of these photogenerated radicals. This conceptual paper delves into the latest advancements in understanding the mechanics of photogenerated radicals.
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Affiliation(s)
- Yao Chen
- MOE Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai, 200234, China
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438, China
| | - Shuyang Xu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438, China
| | - Chun Fang Wen
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | | | - Ting Zhang
- MOE Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai, 200234, China
| | - Fujian Lv
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing, 655400, China
| | - Yinghong Yue
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438, China
| | - Zhenfeng Bian
- MOE Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai, 200234, China
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28
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Zhou YQ, He KC, Zheng WH, Lv JF, He SM, Yu N, Yang YB, Liu LY, Jiang K, Wei Y. 1,5-Hydrogen atom transfer of α-iminyl radical cations: a new platform for relay annulation for pyridine derivatives and axially chiral heterobiaryls. Chem Sci 2024; 15:7502-7514. [PMID: 38784726 PMCID: PMC11110145 DOI: 10.1039/d4sc01858c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
The exploitation of new reactive species and novel transformation modes for their synthetic applications have significantly promoted the development of synthetic organic methodology, drug discovery, and advanced functional materials. α-Iminyl radical cations, a class of distonic ions, exhibit great synthetic potential for the synthesis of valuable molecules. For their generation, radical conjugate addition to α,β-unsaturated iminium ions represents a concise yet highly challenging route, because the in situ generated species are short-lived and highly reactive and they have a high tendency to cause radical elimination (β-scission) to regenerate the more stable iminium ions. Herein, we report a new transformation mode of the α-iminyl radical cation, that is to say, 1,5-hydrogen atom transfer (1,5-HAT). Such a strategy can generate a species bearing multiple reactive sites, which serves as a platform to realize (asymmetric) relay annulations. The present iron/secondary amine synergistic catalysis causes a modular assembly of a broad spectrum of new structurally fused pyridines including axially chiral heterobiaryls, and exhibits good functional group tolerance. A series of mechanistic experiments support the α-iminyl radical cation-induced 1,5-HAT, and the formation of several radical species in the relay annulations. Various synthetic transformations of the reaction products demonstrate the usefulness of this relay annulation protocol for the synthesis of significant molecules.
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Affiliation(s)
- Yu-Qiang Zhou
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Kui-Cheng He
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Wei-Hao Zheng
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Jing-Fang Lv
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Shi-Mei He
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Ning Yu
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Yun-Bo Yang
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Lv-Yan Liu
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Kun Jiang
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
| | - Ye Wei
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University Chongqing 400715 China
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29
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Tang X, Mei S, Xu JF, Zhang X. Supramolecularly modulated carbon-centered radicals: toward selective oxidation from benzyl alcohol to aldehyde. Chem Commun (Camb) 2024; 60:5286-5289. [PMID: 38659373 DOI: 10.1039/d4cc01240b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The reactivity of ketyl radicals and benzoyl radicals, two key intermediates of photo-induced oxidation of benzyl alcohol, can be stabilized by the host-guest interaction of the radicals with cucurbit[7]uril. As a result, the selectivity of photo-induced oxidation from benzyl alcohol to aldehyde is significantly improved by diminishing side reactions and inhibiting the generation of carboxylic acid products. This work presents a new route to modulate the reactivity of radical intermediates, enriching the chemistry of supramolecular intermediates and the toolbox of supramolecular catalysis.
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Affiliation(s)
- Xingchen Tang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Shan Mei
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Jiang-Fei Xu
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Xi Zhang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
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30
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Wang Y, Fan S, Tang X. Nucleophilic Organocatalyst for Photochemical Carbon Radical Generation via S N2 Substitution. Org Lett 2024; 26:4002-4007. [PMID: 38691539 DOI: 10.1021/acs.orglett.4c01278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Photochemical generation of radicals is a powerful way to construct various molecules. But most of these methods rely on initiators or the redox properties of radical precursors. Herein, we report a photochemical organic catalyst that reacts with benzyl halide to generate carbon radical via an SN2 pathway. This nucleophilic catalyst can be easily prepared and is bench-stable. The SN2 process does not rely on the redox properties of halides, showing potential synthetic utility. Control experiments and UV-vis spectroscopic analysis indicate that the SN2 substitution adduct is the key intermediate.
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Affiliation(s)
- Yuzhuo Wang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Shiwen Fan
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Xinjun Tang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
- Zhejiang Institute, China University of Geosciences, Hangzhou 311305, China
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31
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Deng G, Chen Z, Bai Y, Zhang L, Xia D, Duan S, Chen W, Zhang H, Walsh PJ, Yang X. Sulfonamides as N-Centered Radical Precursors for C-N Coupling Reactions To Generate Amidines. Org Lett 2024; 26:3855-3860. [PMID: 38687847 DOI: 10.1021/acs.orglett.4c01014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Nitrogen-centered radicals (NCRs) are valuable intermediates for the construction of C-N bonds. Traditional methods for the generation of NCRs employ toxic radical initiators, transition metal catalysts, photocatalysts, or organometallic reagents. Herein, we report a novel strategy for the generation of NCRs toward the construction of C-N bonds under transition-metal-free conditions. Thus, super-electron-donor (SED) 2-azaallyl anions undergo single-electron transfer (SET) with sulfonamides, forming aminyl radicals (R2N•, R = alkyl) and culminating in the generation of amidines bearing various functional groups (33 examples, up to 96% yield). Broad substrate scope and gram-scale telescoped preparation demonstrate the practicality of this method. Radical clock and electron paramagnetic resonance (EPR) experiments support the proposed radical coupling pathway between the generated N-centered radical and the C-centered 2-azaallyl radical.
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Affiliation(s)
- Guogang Deng
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Zhuo Chen
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Yifeng Bai
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Lening Zhang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Dazhen Xia
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Shengzu Duan
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Wen Chen
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Hongbin Zhang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
| | - Patrick J Walsh
- Roy and Diana Vagelos Laboratories, Penn/Merck Laboratory for High-Throughput Experimentation, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Xiaodong Yang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University, Kunming, Yunnan 650500, People's Republic of China
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32
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Fu H, Hyster TK. From Ground-State to Excited-State Activation Modes: Flavin-Dependent "Ene"-Reductases Catalyzed Non-natural Radical Reactions. Acc Chem Res 2024; 57:1446-1457. [PMID: 38603772 DOI: 10.1021/acs.accounts.4c00129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Enzymes are desired catalysts for chemical synthesis, because they can be engineered to provide unparalleled levels of efficiency and selectivity. Yet, despite the astonishing array of reactions catalyzed by natural enzymes, many reactivity patterns found in small molecule catalysts have no counterpart in the living world. With a detailed understanding of the mechanisms utilized by small molecule catalysts, we can identify existing enzymes with the potential to catalyze reactions that are currently unknown in nature. Over the past eight years, our group has demonstrated that flavin-dependent "ene"-reductases (EREDs) can catalyze various radical-mediated reactions with unparalleled levels of selectivity, solving long-standing challenges in asymmetric synthesis.This Account presents our development of EREDs as general catalysts for asymmetric radical reactions. While we have developed multiple mechanisms for generating radicals within protein active sites, this account will focus on examples where flavin mononucleotide hydroquinone (FMNhq) serves as an electron transfer radical initiator. While our initial mechanistic hypotheses were rooted in electron-transfer-based radical initiation mechanisms commonly used by synthetic organic chemists, we ultimately uncovered emergent mechanisms of radical initiation that are unique to the protein active site. We will begin by covering intramolecular reactions and discussing how the protein activates the substrate for reduction by altering the redox-potential of alkyl halides and templating the charge transfer complex between the substrate and flavin-cofactor. Protein engineering has been used to modify the fundamental photophysics of these reactions, highlighting the opportunity to tune these systems further by using directed evolution. This section highlights the range of coupling partners and radical termination mechanisms available to intramolecular reactions.The next section will focus on intermolecular reactions and the role of enzyme-templated ternary charge transfer complexes among the cofactor, alkyl halide, and coupling partner in gating electron transfer to ensure that it only occurs when both substrates are bound within the protein active site. We will highlight the synthetic applications available to this activation mode, including olefin hydroalkylation, carbohydroxylation, arene functionalization, and nitronate alkylation. This section also discusses how the protein can favor mechanistic steps that are elusive in solution for the asymmetric reductive coupling of alkyl halides and nitroalkanes. We are aware of several recent EREDs-catalyzed photoenzymatic transformations from other groups. We will discuss results from these papers in the context of understanding the nuances of radical initiation with various substrates.These biocatalytic asymmetric radical reactions often complement the state-of-the-art small-molecule-catalyzed reactions, making EREDs a valuable addition to a chemist's synthetic toolbox. Moreover, the underlying principles studied with these systems are potentially operative with other cofactor-dependent proteins, opening the door to different types of enzyme-catalyzed radical reactions. We anticipate that this Account will serve as a guide and inspire broad interest in repurposing existing enzymes to access new transformations.
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Affiliation(s)
- Haigen Fu
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Todd K Hyster
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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33
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Lu YN, Che C, Zhen G, Chang X, Dong XQ, Wang CJ. Visible-light-enabled stereoselective synthesis of functionalized cyclohexylamine derivatives via [4 + 2] cycloadditions. Chem Sci 2024; 15:6507-6514. [PMID: 38699278 PMCID: PMC11062095 DOI: 10.1039/d4sc00667d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 03/26/2024] [Indexed: 05/05/2024] Open
Abstract
An unprecedented intermolecular [4 + 2] cycloaddition of benzocyclobutylamines with α-substituted vinylketones, enabled by photoredox catalysis, has been developed. The current method enables facile access to highly functionalized cyclohexylamine derivatives that were otherwise inaccessible, in moderate to good yields with excellent diastereoselectivities. This protocol has some excellent features, such as full atom economy, good functional-group compatibility, mild reaction conditions, and an overall redox-neutral process. Additionally, an asymmetric version of this cycloaddition was preliminarily investigated via the incorporation of a chiral phosphoric acid (CPA), and moderate to good enantioselectivity could be effectively realized with excellent diastereoselectivity. Synthetic applications were demonstrated via a scale-up experiment and elaborations to access amino alcohol and cyclobutene derivatives. Based on the results of control experiments, a reasonable reaction mechanism was proposed to elucidate the reaction pathway.
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Affiliation(s)
- Yi-Nan Lu
- College of Chemistry and Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University Wuhan Hubei 430072 China
| | - Chao Che
- College of Chemistry and Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University Wuhan Hubei 430072 China
| | - Guangjin Zhen
- College of Chemistry and Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University Wuhan Hubei 430072 China
| | - Xin Chang
- College of Chemistry and Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University Wuhan Hubei 430072 China
| | - Xiu-Qin Dong
- College of Chemistry and Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University Wuhan Hubei 430072 China
| | - Chun-Jiang Wang
- College of Chemistry and Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University Wuhan Hubei 430072 China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry Shanghai 230021 China
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34
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Dinh LP, Starbuck HF, Hamby TB, LaLama MJ, He CQ, Kalyani D, Sevov CS. Persistent organonickel complexes as general platforms for Csp 2-Csp 3 coupling reactions. Nat Chem 2024:10.1038/s41557-024-01528-7. [PMID: 38684816 DOI: 10.1038/s41557-024-01528-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 04/03/2024] [Indexed: 05/02/2024]
Abstract
The importance of constructing Csp2-Csp3 bonds has motivated the development of electrochemical, photochemical and thermal activation methods to reductively couple abundant aryl and alkyl electrophiles. However, these methodologies are limited to couplings of very specific substrate classes and require specialized sets of catalysts and reaction set-ups. Here we show a consolidation of these myriad strategies into a single set of conditions that enable reliable alkyl-aryl couplings, including those that were previously unknown. These reactions rely on the discovery of unusually persistent organonickel complexes that serve as stoichiometric platforms for C(sp2)-C(sp3) coupling. Aryl, heteroaryl or vinyl complexes of Ni can be inexpensively prepared on a multigram scale by mild electroreduction from the corresponding C(sp2) electrophile. Organonickel complexes can be isolated and stored or telescoped directly to reliably diversify drug-like molecules. Finally, the procedure was miniaturized to micromole scales by integrating soluble battery chemistries as redox initiators, enabling a high-throughput exploration of substrate diversity.
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Affiliation(s)
- Long P Dinh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Hunter F Starbuck
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Taylor B Hamby
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Matthew J LaLama
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Cyndi Q He
- Modelling & Informatics, Merck & Co., Inc., Rahway, NJ, USA
| | | | - Christo S Sevov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.
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35
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Li X, Majumder S, Tang X, Dolbier WR. Zinc 1,1,2,2-Tetrafluoroethanesulfinate: A Synthetically Useful Oxidative and Photoredox Source of the 1,1,2,2-Tetrafluoroethyl Radical. J Org Chem 2024; 89:5485-5490. [PMID: 38554099 DOI: 10.1021/acs.joc.3c02948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
1,1,2,2-Tetrafluoroethyl-containing molecules are of potential importance in drug discovery, but the efficient synthesis of such compounds is still relatively unexplored due to the lack of readily available reagents for the incorporation of the HCF2CF2 group. Herein, we introduce a new reagent, zinc 1,1,2,2-tetrafluoroethanesulfinate, which can be useful for the oxidative tetrafluoroethylation of arylboronic acids and heteroarenes as well as for a novel photoredox, three component hydro-tetrafluoroethylation of two alkenes of complementary reactivity.
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Affiliation(s)
- Xinjin Li
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
- College of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, Shandong 255000, China
| | - Satyajit Majumder
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Xiaojun Tang
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - William R Dolbier
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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36
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Sun J, Endo H, Emmanuel MA, Oderinde MS, Kawamata Y, Baran PS. Simplified Modular Access to Enantiopure 1,2-Aminoalcohols via Ni-Electrocatalytic Decarboxylative Arylation. J Am Chem Soc 2024; 146:6209-6216. [PMID: 38387466 PMCID: PMC10962872 DOI: 10.1021/jacs.3c14119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024]
Abstract
Chiral aminoalcohols are omnipresent in bioactive compounds. Conventional strategies to access this motif involve multiple-step reactions to install the requisite functionalities stereoselectively using conventional polar bond analysis. This study reveals that a simple chiral oxazolidine-based carboxylic acid can be readily transformed to substituted chiral aminoalcohols with high stereochemical control by Ni-electrocatalytic decarboxylative arylation. This general, robust, and scalable coupling can be used to synthesize a variety of medicinally important compounds, avoiding protecting and functional group manipulations, thereby dramatically simplifying their preparation.
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Affiliation(s)
- Jiawei Sun
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Hirofumi Endo
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Megan A. Emmanuel
- Chemical
Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, New Jersey 08901, United States
| | - Martins S. Oderinde
- Small
Molecule Drug Discovery, Bristol Myers Squibb
Research & Early Development, Route 206 & Province Line Road, Princeton, New Jersey 08543, United States
| | - Yu Kawamata
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Phil S. Baran
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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37
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Azpilcueta-Nicolas CR, Lumb JP. Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters. Beilstein J Org Chem 2024; 20:346-378. [PMID: 38410775 PMCID: PMC10896223 DOI: 10.3762/bjoc.20.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/29/2024] [Indexed: 02/28/2024] Open
Abstract
Due to their ease of preparation, stability, and diverse reactivity, N-hydroxyphthalimide (NHPI) esters have found many applications as radical precursors. Mechanistically, NHPI esters undergo a reductive decarboxylative fragmentation to provide a substrate radical capable of engaging in diverse transformations. Their reduction via single-electron transfer (SET) can occur under thermal, photochemical, or electrochemical conditions and can be influenced by a number of factors, including the nature of the electron donor, the use of Brønsted and Lewis acids, and the possibility of forming charge-transfer complexes. Such versatility creates many opportunities to influence the reaction conditions, providing a number of parameters with which to control reactivity. In this perspective, we provide an overview of the different mechanisms for radical reactions involving NHPI esters, with an emphasis on recent applications in radical additions, cyclizations and decarboxylative cross-coupling reactions. Within these reaction classes, we discuss the utility of the NHPI esters, with an eye towards their continued development in complexity-generating transformations.
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Affiliation(s)
| | - Jean-Philip Lumb
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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38
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Mato M, Cornella J. Bismuth in Radical Chemistry and Catalysis. Angew Chem Int Ed Engl 2024; 63:e202315046. [PMID: 37988225 DOI: 10.1002/anie.202315046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/23/2023]
Abstract
Whereas indications of radical reactivity in bismuth compounds can be traced back to the 19th century, the preparation and characterization of both transient and persistent bismuth-radical species has only been established in recent decades. These advancements led to the emergence of the field of bismuth radical chemistry, mirroring the progress seen for other main-group elements. The seminal and fundamental studies in this area have ultimately paved the way for the development of catalytic methodologies involving bismuth-radical intermediates, a promising approach that remains largely untapped in the broad landscape of synthetic organic chemistry. In this review, we delve into the milestones that eventually led to the present state-of-the-art in the field of radical bismuth chemistry. Our focus aims at outlining the intrinsic discoveries in fundamental inorganic/organometallic chemistry and contextualizing their practical applications in organic synthesis and catalysis.
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Affiliation(s)
- Mauro Mato
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Josep Cornella
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
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39
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Mizuno A, Matsuoka R, Mibu T, Kusamoto T. Luminescent Radicals. Chem Rev 2024; 124:1034-1121. [PMID: 38230673 DOI: 10.1021/acs.chemrev.3c00613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Organic radicals are attracting increasing interest as a new class of molecular emitters. They demonstrate electronic excitation and relaxation dynamics based on their doublet or higher multiplet spin states, which are different from those based on singlet-triplet manifolds of conventional closed-shell molecules. Recent studies have disclosed luminescence properties and excited state dynamics unique to radicals, such as highly efficient electron-photon conversion in OLEDs, NIR emission, magnetoluminescence, an absence of heavy atom effect, and spin-dependent and spin-selective dynamics. These are difficult or sometimes impossible to achieve with closed-shell luminophores. This review focuses on luminescent organic radicals as an emerging photofunctional molecular system, and introduces the material developments, fundamental properties including luminescence, and photofunctions. Materials covered in this review range from monoradicals, radical oligomers, and radical polymers to metal complexes with radical ligands demonstrating radical-involved emission. In addition to stable radicals, transiently formed radicals generated in situ by external stimuli are introduced. This review shows that luminescent organic radicals have great potential to expand the chemical and spin spaces of luminescent molecular materials and thus broaden their applicability to photofunctional systems.
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Affiliation(s)
- Asato Mizuno
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Ryota Matsuoka
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, HayamaKanagawa 240-0193, Japan
| | - Takuto Mibu
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Tetsuro Kusamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, HayamaKanagawa 240-0193, Japan
- JST-PRESTO, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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40
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Wu BL, Yao JN, Long XX, Tan ZQ, Liang X, Feng L, Wei K, Yang YR. Enantioselective Total Synthesis of (-)-Daphenylline. J Am Chem Soc 2024; 146:1262-1268. [PMID: 38180776 DOI: 10.1021/jacs.3c12741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
A concise enantioselective total synthesis of (-)-daphenylline, a hexacyclic Daphniphyllum alkaloid with a unique benzene ring, was achieved in 14 steps. The synthesis commences with two chiral stereocenters, C2 and C18, readily installed via Carreira's Ir/amine dual-catalyzed allylation. The allylic bridgehead amine 6 was rapidly prepared through Wickens' photoredox-catalyzed hydrocarboxylation of olefin and CuBr2-catalyzed α-amination of ketone. The tetracycle 4 was formed via Pd-catalyzed reductive Heck reaction or, more concisely, by Krische's Rh-catalyzed reductive 1,6-enyne cyclization. In this synthesis, newly reported Wickens' photoredox-catalyzed hydrocarboxylation was used twice, and Friedel-Crafts acylation thrice.
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Affiliation(s)
- Bing-Lu Wu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian-Neng Yao
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Xiang-Xi Long
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zong-Qin Tan
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Liang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Li Feng
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kun Wei
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Yu-Rong Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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41
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Wang Y, Deng J, Ressler AJ, Lin S. Electroreductive Radical Addition-Polar Cyclization Cascade to Access Cycloalkanes. Org Lett 2024; 26:116-121. [PMID: 38157449 PMCID: PMC11192528 DOI: 10.1021/acs.orglett.3c03722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Compared with flat aromatic scaffolds, three-dimensional aliphatic ring systems feature high structural complexity and topological diversity and, thus, have received increasing attention in drug discovery. Herein, we describe a mild and general electrochemical method for the modular synthesis of structurally distinct cyclic compounds, including monocyclic alkanes, benzo-fused ring systems, and spirocycles, from readily available alkenes and alkyl halides via a radical-polar crossover mechanism.
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Affiliation(s)
- Yi Wang
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
| | - Jiachen Deng
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
| | - Andrew J. Ressler
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, New York 14853, United States
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42
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Kubota K, Jiang J, Kamakura Y, Hisazumi R, Endo T, Miura D, Kubo S, Maeda S, Ito H. Using Mechanochemistry to Activate Commodity Plastics as Initiators for Radical Chain Reactions of Small Organic Molecules. J Am Chem Soc 2024; 146:1062-1070. [PMID: 38134051 DOI: 10.1021/jacs.3c12049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Radical initiators such as azo compounds and organic peroxides have been widely used to facilitate numerous transformations of free radicals, which enable the efficient synthesis of structurally complex molecules, natural products, polymers, and functional materials. However, these high-energy reagents are potentially explosive and thus often require special precautions or delicate operating conditions. We postulated that a more convenient and safer alternative for radical chain initiation could be developed by mechanical activation of thermodynamically stable covalent bonds. Here, we show that commodity plastics such as polyethylene and poly(vinyl acetate) are capable of acting as efficient initiators for radical chain reactions under solvent-free mechanochemical conditions. In this approach, polymeric mechanoradicals, which are generated by homolytic cleavage of the polymer chains in response to the applied mechanical energy provided by ball milling, react with tris(trimethylsilyl)silane to initiate radical chain dehalogenation of organic halides. Preliminary calculations support our proposed force-induced radical chain mechanism.
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Affiliation(s)
- Koji Kubota
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Hokkaido, Japan
| | - Julong Jiang
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Yuri Kamakura
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Reon Hisazumi
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Tsubura Endo
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Daiyo Miura
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Shotaro Kubo
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Satoshi Maeda
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Hokkaido, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Hajime Ito
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Hokkaido, Japan
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43
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Xu J, Lan Y, Liu B. Activation of Aryl and Alkyl Halides Enabled by Strong Photoreduction Potentials of a Hantzsch Ester/Cs 2CO 3 System. J Org Chem 2024; 89:599-604. [PMID: 38113916 DOI: 10.1021/acs.joc.3c02320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
We disclose herein a light-induced Hantzsch ester-initiated aryl and alkyl radical generation protocol from aryl halides (Br and Cl) and alkyl iodides. This method provides access to a wide range of benzo-fused heterocycles and C(sp3)-C(sp3) coupling products. The reductive detosylation reaction has also been demonstrated using the same reaction conditions. Initial mechanism studies provide evidence of the formation of an alkyl radical.
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Affiliation(s)
- Junhua Xu
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Yingjun Lan
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Bin Liu
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
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44
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Xu Y, Chen H, Yu L, Peng X, Zhang J, Xing Z, Bao Y, Liu A, Zhao Y, Tian C, Liang Y, Huang X. A light-driven enzymatic enantioselective radical acylation. Nature 2024; 625:74-78. [PMID: 38110574 DOI: 10.1038/s41586-023-06822-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/01/2023] [Indexed: 12/20/2023]
Abstract
Enzymes are recognized as exceptional catalysts for achieving high stereoselectivities1-3, but their ability to control the reactivity and stereoinduction of free radicals lags behind that of chemical catalysts4. Thiamine diphosphate (ThDP)-dependent enzymes5 are well-characterized systems that inspired the development of N-heterocyclic carbenes (NHCs)6-8 but have not yet been proved viable in asymmetric radical transformations. There is a lack of a biocompatible and general radical-generation mechanism, as nature prefers to avoid radicals that may be harmful to biological systems9. Here we repurpose a ThDP-dependent lyase as a stereoselective radical acyl transferase (RAT) through protein engineering and combination with organophotoredox catalysis10. Enzyme-bound ThDP-derived ketyl radicals are selectively generated through single-electron oxidation by a photoexcited organic dye and then cross-coupled with prochiral alkyl radicals with high enantioselectivity. Diverse chiral ketones are prepared from aldehydes and redox-active esters (35 examples, up to 97% enantiomeric excess (e.e.)) by this method. Mechanistic studies reveal that this previously elusive dual-enzyme catalysis/photocatalysis directs radicals with the unique ThDP cofactor and evolvable active site. This work not only expands the repertoire of biocatalysis but also provides a unique strategy for controlling radicals with enzymes, complementing existing chemical tools.
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Affiliation(s)
- Yuanyuan Xu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Hongwei Chen
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Lu Yu
- The Anhui Provincial Key Laboratory of High Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Xichao Peng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Jiawei Zhang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Zhongqiu Xing
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yuyan Bao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Aokun Liu
- The Anhui Provincial Key Laboratory of High Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Changlin Tian
- The Anhui Provincial Key Laboratory of High Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Joint Center for Biological Analytical Chemistry, Anhui Engineering Laboratory of Peptide Drug, Anhui Laboratory of Advanced Photonic Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
- Henan-Macquarie University Joint Centre for Biomedical Innovation, School of Life Sciences, Henan University, Kaifeng, China.
| | - Xiaoqiang Huang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
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45
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Sheng N, He C, Jin X, Meng Q, Gu P, Ding S, Liu H, Xu Y. A comprehensive study of oxidative stress-related effects on the prognosis and drug therapy of cervical cancer. J Gene Med 2024; 26:e3581. [PMID: 37605936 DOI: 10.1002/jgm.3581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 07/18/2023] [Accepted: 07/31/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND Cervical cancer (CC) is a serious global disease with poor prognoses and a significant recurrence rate in patients with advanced disease. Oxidative stress (OS) greatly influences many types of human cancers, making it crucial to understand the functional mechanisms of OS-related genes in CC. METHODS The transcriptome and clinical data of three normal samples and 306 patients with CC were obtained from The Cancer Genome Atlas dataset. The GSE44001 dataset was acquired from the Gene Expression Omnibus database. OS-related subtypes in the cohort with CC were identified using unsupervised hierarchical clustering, univariate Cox analysis, gene set enrichment analysis (GSEA), and least absolute shrinkage and selection operator regression analysis. Additionally, molecular pathways that differ across subtypes were determined and OS-related genes linked to the prognosis of patients of CC were determined. Finally, a clinical prognostic gene signature was developed and validated. The relative infiltration level of immune cell subpopulations in different risk groups and subtypes was evaluated using the cell-type identification by estimating relative subsets of RNA transcripts (CIBERPORT) algorithm and single-sample GSEA (ssGSEA) techniques. RESULTS The present study established two distinct OS subtypes (OS clusters A and B). Analysis using ssGSEA and CIBERSPORT revealed that OS cluster B exhibited a significant level of immune infiltration. A clinical prognostic gene signature was established using OS-related characteristic genes identified by examining the differentially expressed genes across both subtypes. Furthermore, patients with CC were grouped into high- and low-risk groups, with the low-risk group showing higher survival rates. Additionally, these individuals exhibited significant advantages in terms of survival and immunotherapy. Receiver operating characteristic curve analysis demonstrated the higher predictive value of the clinical prognostic gene signature. The outcomes of the validation group depicted congruence with those recorded in the training group. CONCLUSIONS A new model was constructed based on eight OS-related characteristic genes to aid the prediction of the survival rates of individuals with CC. The present study contributes to the existing literature on the mechanisms of OS genes in CC and offers a fresh perspective for future advancements in immunotherapy for such individuals.
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Affiliation(s)
- Nan Sheng
- Department of Obstetrics and Gynecology, Affiliated Hospital of Nantong University, Nantong, China
| | - Chenyun He
- Department of Gynecology Oncology, Nantong Tumor Hospital, Tumor Hospital Affiliated to Nantong University, Nantong, China
| | - Xiaoxia Jin
- Department of Pathology, Nantong Tumor Hospital, Tumor Hospital Affiliated to Nantong University, Nantong, China
| | - Qi Meng
- Department of Obstetrics and Gynecology, Affiliated Hospital of Nantong University, Nantong, China
| | - Panyun Gu
- Department of Obstetrics and Gynecology, Affiliated Hospital of Nantong University, Nantong, China
| | - Shu Ding
- Department of Obstetrics and Gynecology, Affiliated Hospital of Nantong University, Nantong, China
| | - Hong Liu
- Department of Hematology, Affiliated Hospital of Nantong University, Nantong, China
| | - Yunzhao Xu
- Department of Obstetrics and Gynecology, Affiliated Hospital of Nantong University, Nantong, China
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46
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Xie ZZ, Liao ZH, Zheng Y, Yuan CP, Guan JP, Li MZ, Deng KY, Xiang HY, Chen K, Yang H. Photoredox-Catalyzed Selective α-Scission of PR 3-OH Radicals to Access Hydroalkylation of Alkenes. Org Lett 2023; 25:9014-9019. [PMID: 38063439 DOI: 10.1021/acs.orglett.3c03632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Photoinduced generation of phosphoranyl radicals offers a versatile strategy to access a variety of synthetically valuable radicals. A long-standing challenge remains in the regulation of phosphoranyl radical to undergo α-scission pathway, although the β-scission mode has been intensively studied. We herein developed an unprecedented protocol for selective α-scission of the P(OH)R3 radical intermediate under photocatalytic conditions. This efficient P-C bond cleavage via α-scission of the P(OH)R3 radicals has been successfully utilized in the alkylation/fluoroalkylation of alkenes.
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Affiliation(s)
- Zhen-Zhen Xie
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Zi-Hao Liao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Yu Zheng
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, P. R. China
| | - Chu-Ping Yuan
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Jian-Ping Guan
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Ming-Zhi Li
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Ke-Yi Deng
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Hao-Yue Xiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Kai Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Hua Yang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
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47
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Bian KJ, Nemoto D, Chen XW, Kao SC, Hooson J, West JG. Photocatalytic, modular difunctionalization of alkenes enabled by ligand-to-metal charge transfer and radical ligand transfer. Chem Sci 2023; 15:124-133. [PMID: 38131080 PMCID: PMC10732012 DOI: 10.1039/d3sc05231a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/09/2023] [Indexed: 12/23/2023] Open
Abstract
Ligand-to-metal charge transfer (LMCT) is a mechanistic strategy that provides a powerful tool to access diverse open-shell species using earth abundant elements and has seen tremendous growth in recent years. However, among many reaction manifolds driven by LMCT reactivity, a general and catalytic protocol for modular difunctionalization of alkenes remains unknown. Leveraging the synergistic cooperation of iron-catalyzed ligand-to-metal charge transfer and radical ligand transfer (RLT), here we report a photocatalytic, modular difunctionalization of alkenes using inexpensive iron salts catalytically to function as both radical initiator and terminator. Additionally, strategic use of a fluorine atom transfer reagent allows for general fluorochlorination of alkenes, providing the first example of interhalogen compound formation using earth abundant element photocatalysis. Broad scope, mild conditions and versatility in converting orthogonal nucleophiles (TMSN3 and NaCl) directly into corresponding open-shell radical species are demonstrated in this study, providing a robust means towards accessing vicinal diazides and homo-/hetero-dihalides motifs catalytically. These functionalities are important precursors/intermediates in medicinal and material chemistry. Preliminary mechanistic studies support the radical nature of these transformations, disclosing the tandem LMCT/RLT as a powerful reaction manifold in catalytic olefin difunctionalization.
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Affiliation(s)
- Kang-Jie Bian
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - David Nemoto
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - Xiao-Wei Chen
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - Shih-Chieh Kao
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - James Hooson
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - Julian G West
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
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48
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Dawson G, Spielvogel EH, Diao T. Nickel-Catalyzed Radical Mechanisms: Informing Cross-Coupling for Synthesizing Non-Canonical Biomolecules. Acc Chem Res 2023; 56:3640-3653. [PMID: 38033206 PMCID: PMC10734253 DOI: 10.1021/acs.accounts.3c00588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 12/02/2023]
Abstract
Nickel excels at facilitating selective radical chemistry, playing a pivotal role in metalloenzyme catalysis and modern cross-coupling reactions. Radicals, being nonpolar and neutral, exhibit orthogonal reactivity to nucleophilic and basic functional groups commonly present in biomolecules. Harnessing this compatibility, we delve into the application of nickel-catalyzed radical pathways in the synthesis of noncanonical peptides and carbohydrates, critical for chemical biology studies and drug discovery.We previously characterized a sequential reduction mechanism that accounts for chemoselectivity in cross-electrophile coupling reactions. This catalytic cycle begins with nickel(I)-mediated radical generation from alkyl halides, followed by carbon radical capture by nickel(II) complexes, and concludes with reductive elimination. These steps resonate with mechanistic proposals in nickel-catalyzed cross-coupling, photoredox, and electrocatalytic reactions. Herein, we present our insights into each step involving radicals, including initiation, propagation, termination, and the nuances of kinetics, origins of selectivity, and ligand effects.Radical generation from C(sp3) electrophiles via one-electron oxidative addition with low-valent nickel radical intermediates provides the basis for stereoconvergent and cross-electrophile couplings. Our electroanalytical studies elucidate a concerted halogen atom abstraction mechanism, where electron transfer is coupled with halide dissociation. Using this pathway, we have developed a nickel-catalyzed stereoselective radical addition to dehydroalanine, facilitating the synthesis of noncanonical peptides. In this application, chiral ligands modulate the stereochemical outcome through the asymmetric protonation of a nickel-enolate intermediate.The capture of the alkyl radical by nickel(II) expands the scope of cross-coupling, promotes reductive elimination through the formation of high-valent nickel(III) species, and governs chemo- and stereoselectivity. We discovered that nickel(II)-aryl efficiently traps radicals with a barrier ranging from 7 to 9 kcal/mol, followed by fast reductive elimination. In contrast, nickel(II)-alkyl captures radicals to form a nickel(III) species, which was characterized by EPR spectroscopy. However, the subsequent slow reductive elimination resulted in minimal product formation. The observed high diastereoselectivity of radical capture inspired investigations into C-aryl and C-acyl glycosylation reactions. We developed a redox auxiliary that readily couples with natural carbohydrates and produces glycosyl radicals upon photoredox activation. Nickel-catalyzed cross-coupling of the glycosyl radical with bromoarenes and carboxylic acids leads to diverse non-natural glycosides that can facilitate drug discovery.Stoichiometric studies on well-defined d8-nickel complexes have showcased means to promote reductive elimination, including ligand association, oxidation, and oxidative addition.In the final section, we address the influence of auxiliary ligands on the electronic structure and redox activity of organonickel intermediates. Synthesis of a series of low-valent nickel radical complexes and characterization of their electronic structures led us to a postulate that ligand redox activity correlates with coordination geometry. Our data reveal that a change in ligand redox activity can shift the redox potentials of reaction intermediates, potentially altering the mechanism of catalytic reactions. Moreover, coordinating additives and solvents may stabilize nickel radicals during catalysis by adjusting ligand redox activity, which is consistent with known catalytic conditions.
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Affiliation(s)
- Gregory
A. Dawson
- Department
of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States
| | - Ethan H. Spielvogel
- Department
of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States
| | - Tianning Diao
- Department
of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States
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49
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Wang CL, Wang J, Jin JK, Li B, Phang YL, Zhang FL, Ye T, Xia HM, Hui LW, Su JH, Fu Y, Wang YF. Boryl radical catalysis enables asymmetric radical cycloisomerization reactions. Science 2023; 382:1056-1065. [PMID: 38033072 DOI: 10.1126/science.adg1322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 10/25/2023] [Indexed: 12/02/2023]
Abstract
The development of functionally distinct catalysts for enantioselective synthesis is a prominent yet challenging goal of synthetic chemistry. In this work, we report a family of chiral N-heterocyclic carbene (NHC)-ligated boryl radicals as catalysts that enable catalytic asymmetric radical cycloisomerization reactions. The radical catalysts can be generated from easily prepared NHC-borane complexes, and the broad availability of the chiral NHC component provides substantial benefits for stereochemical control. Mechanistic studies support a catalytic cycle comprising a sequence of boryl radical addition, hydrogen atom transfer, cyclization, and elimination of the boryl radical catalyst, wherein the chiral NHC subunit determines the enantioselectivity of the radical cyclization. This catalysis allows asymmetric construction of valuable chiral heterocyclic products from simple starting materials.
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Affiliation(s)
- Chang-Ling Wang
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jie Wang
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ji-Kang Jin
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bin Li
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yee Lin Phang
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Feng-Lian Zhang
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tian Ye
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hui-Min Xia
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Li-Wen Hui
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ji-Hu Su
- Chinese Academy of Sciences Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Yao Fu
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yi-Feng Wang
- Key Laboratory of Precision and Intelligent Chemistry, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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50
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Skinner KC, Kammeraad JA, Wymore T, Narayan ARH, Zimmerman PM. Simulating Electron Transfer Reactions in Solution: Radical-Polar Crossover. J Phys Chem B 2023; 127:10097-10107. [PMID: 37976536 PMCID: PMC11135460 DOI: 10.1021/acs.jpcb.3c06120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Single-electron transfer (SET) promotes a wide variety of interesting chemical transformations, but modeling of SET requires a careful treatment of electronic and solvent effects to give meaningful insight. Therefore, a combined constrained density functional theory and molecular mechanics (CDFT/MM) tool is introduced specifically for SET-initiated reactions. Mechanisms for two radical-polar crossover reactions involving the organic electron donors tetrakis(dimethylamino)ethylene (TDAE) and tetrathiafulvalene (TTF) were studied with the new tool. An unexpected tertiary radical intermediate within the TDAE system was identified, relationships between kinetics and substitution in the TTF system were explained, and the impact of the solvent environments on the TDAE and TTF reactions were examined. The results highlight the need for including solvent dynamics when quantifying SET kinetics and thermodynamics, as a free energy difference of >20 kcal/mol was observed. Overall, the new method informs mechanistic analysis of SET-initiated reactions and therefore is envisioned to be useful for studying reactions in the condensed phase.
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Affiliation(s)
- Kevin C Skinner
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Josh A Kammeraad
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Troy Wymore
- Laufer Center, Stony Brook University, Stony Brook, New York 11794, United States
| | - Alison R H Narayan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Paul M Zimmerman
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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