1
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Cao S, Chen JX, Zhang XL, Song X, Song WY, Wu YS, Zhang YH, Liu Z. Merging Quinoxalin-2(1 H)-ones Excitation with Cobaloxime Catalysis: C3 Alkylation of Quinoxalin-2(1 H)-ones with Unactivated Alkyl Iodides and Carboxylic Acids under Light. Org Lett 2024. [PMID: 38934368 DOI: 10.1021/acs.orglett.4c02021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
Reported herein is a practical, economical, and efficient construction of 3-alkylated quinoxalin-2(1H)-ones with alkyl carboxylic acids and alkyl iodides by quinoxalin-2(1H)-one excitation and cobaloxime catalysis. Primary, secondary, and tertiary alkyl iodides and carboxylic acids all could be efficiently transferred into target products with excellent functional group tolerance. Mechanism studies reveal that the quinoxalin-2(1H)-one derivatives could be directly excited and yield alkyl carbon radicals from alkyl carboxylic acids and alkyl iodides with the aid of the cobaloxime complex.
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Affiliation(s)
- Shuo Cao
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
| | - Jia-Xin Chen
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
| | - Xiu-Li Zhang
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
| | - Xian Song
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
| | - Wen-Yu Song
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
| | - Yu-Sheng Wu
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
| | - Yan-Hui Zhang
- School of Medical Imaging, Shandong Second Medical University Weifang, 261053 China
| | - Zan Liu
- School of Pharmacy, Shandong Second Medical University Weifang, 261053 China
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2
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Carré V, Godard P, Méreau R, Jacquot de Rouville HP, Jonusauskas G, McClenaghan N, Tassaing T, Vincent JM. Photogeneration of Chlorine Radical from a Self-Assembled Fluorous 4CzIPN•Chloride Complex: Application in C-H Bond Functionalization. Angew Chem Int Ed Engl 2024; 63:e202402964. [PMID: 38634355 DOI: 10.1002/anie.202402964] [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: 02/12/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 04/19/2024]
Abstract
The chlorine radical is a strong HAT (Hydrogen Atom Transfer) agent that is very useful for the functionalization of C(sp3)-H bonds. Albeit highly attractive, its generation from the poorly oxidizable chloride ion mediated by an excited photoredox catalyst is a difficult task. We now report that 8Rf8-4CzIPN, an electron-deficient fluorous derivative of the benchmark 4CzIPN photoredox catalyst belonging to the donor-acceptor carbazole-cyanoarene family, is not only a better photooxidant than 4CzIPN, but also becomes an excellent host for the chloride ion. Combining these two properties ultimately makes the self-assembled 8Rf8-4CzIPN•Cl- dual catalyst highly reactive in redox-neutral Giese-type C(sp3)-H bond alkylation reactions promoted by the chlorine radical. Additionally, because of its fluorous character, the efficient separation/recovery of 8Rf8-4CzIPN could be envisioned.
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Affiliation(s)
- Victor Carré
- Institut des Sciences Moléculaires, CNRS UMR 5255, Université de Bordeaux, 351, Crs de la Libération, 33405, Talence, France
| | - Pascale Godard
- Institut des Sciences Moléculaires, CNRS UMR 5255, Université de Bordeaux, 351, Crs de la Libération, 33405, Talence, France
| | - Raphaël Méreau
- Institut des Sciences Moléculaires, CNRS UMR 5255, Université de Bordeaux, 351, Crs de la Libération, 33405, Talence, France
| | | | - Gediminas Jonusauskas
- Laboratoire Ondes et Matière d'Aquitaine, CNRS UMR 5798, Univ. Bordeaux, 351, Crs de la Libération, 33405, Talence, France
| | - Nathan McClenaghan
- Institut des Sciences Moléculaires, CNRS UMR 5255, Université de Bordeaux, 351, Crs de la Libération, 33405, Talence, France
| | - Thierry Tassaing
- Institut des Sciences Moléculaires, CNRS UMR 5255, Université de Bordeaux, 351, Crs de la Libération, 33405, Talence, France
| | - Jean-Marc Vincent
- Institut des Sciences Moléculaires, CNRS UMR 5255, Université de Bordeaux, 351, Crs de la Libération, 33405, Talence, France
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3
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Zhao X, Hou YL, Qian BC, Shen GB. Thermodynamic H-Abstraction Abilities of Nitrogen Centered Radical Cations as Potential Hydrogen Atom Transfer Catalysts in Y-H Bond Functionalization. ACS OMEGA 2024; 9:26708-26718. [PMID: 38911737 PMCID: PMC11191127 DOI: 10.1021/acsomega.4c04209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 05/20/2024] [Accepted: 05/23/2024] [Indexed: 06/25/2024]
Abstract
Y-H bond functionalization has always been the focus of research interest in the area of organic synthesis. Direct hydrogen atom transfer (HAT) from the Y-H bond is one of the most efficient and practical methods to activate the Y-H bond. Recently, nitrogen centered radical cations were broadly utilized as H-abstraction catalysts to activate Y-H bonds via the HAT process. As a type of HAT catalyst, the H-affinity of nitrogen centered radical cations is a significant thermodynamic parameter to quantitatively evaluate the thermodynamic H-abstraction potentials of nitrogen centered radical cations. In this work, the pK a values of 120 protonated N-containing compounds in acetonitrile (AN) are predicted, and the H-affinities of 120 nitrogen centered radical cations in AN are derived from the reduction potentials of nitrogen centered radical cations and pK a of protonated N-containing compounds using Hess' law. This work focuses on the H-abstraction abilities of 120 nitrogen centered radical cations in AN to enrich the molecule library of novel HAT catalysts or H-abstractors and provides valuable thermodynamic guidelines for the application of nitrogen centered radical cations in Y-H bond functionalization.
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Affiliation(s)
- Xia Zhao
- College of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Yi-Lin Hou
- College of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Bao-Chen Qian
- College of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Guang-Bin Shen
- College of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
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4
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Sun K, Sun T, Jiang Y, Shi J, Sun W, Zheng Y, Wang Z, Li Z, Lv X, Zhang X, Luo F, Liu S. Iron-catalyzed benzylic C-H thiolation via photoinduced ligand-to-metal charge-transfer. Chem Commun (Camb) 2024; 60:5755-5758. [PMID: 38747147 DOI: 10.1039/d4cc01574f] [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
Here, we describe an iron-catalyzed benzylic C-H thiolation of alkylarenes via photoinduced ligand-to-metal charge-transfer. The protocol features operational simplicity, mild reaction conditions, and the use of FeCl3 as catalyst and thiols/disulfides as sulfur sources, which enables the transformation of diverse benzylic C-H bonds into C-S bonds with a high efficiency.
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Affiliation(s)
- Kaiting Sun
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Tianyi Sun
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Yuxin Jiang
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Jiayue Shi
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Wenlu Sun
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Youyou Zheng
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Zhixuan Wang
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Ziyu Li
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Xiaoqing Lv
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Xingxian Zhang
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
| | - Fan Luo
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
| | - Shihui Liu
- College of Medicine, Jiaxing University, 118 Jiahang Road, Jiaxing, 314001, P. R. China.
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5
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Ge L, Wang H, Liu Y, Feng X. Asymmetric Three-Component Radical Alkene Carboazidation by Direct Activation of Aliphatic C-H Bonds. J Am Chem Soc 2024; 146:13347-13355. [PMID: 38710023 DOI: 10.1021/jacs.4c02012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Azide compounds are widely present in natural products and drug molecules, and their easy-to-transform characteristics make them widely used in the field of organic synthesis. The merging of transition-metal catalysis with radical chemistry offers a versatile platform for radical carboazidation of alkenes, allowing the rapid assembly of highly functionalized organic azides. However, the direct use of readily available hydrocarbon feedstocks as sp3-hybridized carbon radical precursors to participate in catalytic enantioselective carboazidation of alkenes remains a significant challenge that has yet to be addressed. Herein, we describe an iron-catalyzed asymmetric three-component radical carboazidation of electron-deficient alkenes by direct activation of aliphatic C-H bonds. This approach involves intermolecular hydrogen atom transfer between a hydrocarbon and an alkoxy/aryl carboxyl radical, leading to the formation of a carbon-centered radical. The resulting radical then reacts with electron-deficient alkenes to generate a new radical species that undergoes chiral iron-complex-mediated C-N3 bond coupling. An array of valuable chiral azides bearing a quaternary stereocenter were directly accessed from widely available chemical feedstocks, and their synthetic potential is further demonstrated through more facile transformations to give other valuable enantioenriched building blocks.
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Affiliation(s)
- Liang Ge
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University, Shenzhen Graduate School, Shenzhen 518055, P. R. China
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen 518132, P. R. China
| | - Hongkai Wang
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen 518132, P. R. China
| | - Yangbin Liu
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen 518132, P. R. China
| | - Xiaoming Feng
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen 518132, P. R. China
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
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6
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Yang JF, Liu YF, Wei LL, Qiao KK, Zhao YQ, Shi L. Minisci-Type Dehydrogenative Coupling of N-Heteroaromatic Rings with Inert C(sp 3)-H Enabled by a Visible-Light-Catalyzed Intermolecular Hydrogen Atom Transfer Process. J Org Chem 2024; 89:4249-4260. [PMID: 38443760 DOI: 10.1021/acs.joc.4c00093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
The Minisci-type dehydrogenative coupling of N-heteroaromatic rings with inert C-H or Si-H partners via visible-light-catalyzed hydrogen atom transfer has been reported. This methodology allows the coupling reactions to be carried out in water as a solvent under air atmospheric conditions with visible-light illumination. A wide range of inert C-H and Si-H partners could be directly coupled with various N-aromatic heterocycles to deliver products in good to excellent yields.
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Affiliation(s)
- Jun-Feng Yang
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Yun-Fei Liu
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Lin-Lin Wei
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Kai-Kai Qiao
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Yan-Qiu Zhao
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Lei Shi
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
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7
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Shi Q, Kang XW, Liu Z, Sakthivel P, Aman H, Chang R, Yan X, Pang Y, Dai S, Ding B, Ye J. Single-Electron Oxidation-Initiated Enantioselective Hydrosulfonylation of Olefins Enabled by Photoenzymatic Catalysis. J Am Chem Soc 2024; 146:2748-2756. [PMID: 38214454 DOI: 10.1021/jacs.3c12513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Controlling the enantioselectivity of hydrogen atom transfer (HAT) reactions has been a long-standing synthetic challenge. While recent advances on photoenzymatic catalysis have demonstrated the great potential of non-natural photoenzymes, all of the transformations are initiated by single-electron reduction of the substrate, with only one notable exception. Herein, we report an oxidation-initiated photoenzymatic enantioselective hydrosulfonylation of olefins using a novel mutant of gluconobacter ene-reductase (GluER-W100F-W342F). Compared to known photoenzymatic systems, our approach does not rely on the formation of an electron donor-acceptor complex between the substrates and enzyme cofactor and simplifies the reaction system by obviating the addition of a cofactor regeneration mixture. More importantly, the GluER variant exhibits high reactivity and enantioselectivity and a broad substrate scope. Mechanistic studies support the proposed oxidation-initiated mechanism and reveal that a tyrosine-mediated HAT process is involved.
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Affiliation(s)
- Qinglong Shi
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiu-Wen Kang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhiyong Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pandaram Sakthivel
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hasil Aman
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Chang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoyu Yan
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yubing Pang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shaobo Dai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bei Ding
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Juntao Ye
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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8
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Hosaka M, Nagasawa S, Iwabuchi Y. C-H Alkylation of Cubanes via Catalytic Generation of Cubyl Radicals. Org Lett 2024; 26:658-663. [PMID: 38236029 DOI: 10.1021/acs.orglett.3c04019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
A catalytic method for the C-H alkylation of cubanes is described. Some hydrogen atom transfer catalysts enable the direct abstraction of a hydrogen atom from the C-H bond of cubanes, followed by conjugate addition of the generated cubyl radicals to electron-deficient alkenes. Synthetic applications of the functionalization method developed are also described.
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Affiliation(s)
- Masaki Hosaka
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
| | - Shota Nagasawa
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
| | - Yoshiharu Iwabuchi
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
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9
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Cao J, Zhu JL, Scheidt KA. Photoinduced cerium-catalyzed C-H acylation of unactivated alkanes. Chem Sci 2023; 15:154-159. [PMID: 38131082 PMCID: PMC10732008 DOI: 10.1039/d3sc05162e] [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: 09/29/2023] [Accepted: 11/09/2023] [Indexed: 12/23/2023] Open
Abstract
Ketones are ubiquitous motifs in the realm of pharmaceuticals and natural products. Traditional approaches to accessing these species involve the addition of metal reagents to carboxyl compounds under harsh conditions. Herein, we report a cerium-catalyzed acylation of unactivated C(sp3)-H bonds using bench-stable acyl azolium reagents under mild and operationally-friendly conditions. This reaction exhibits excellent generality, accommodating a wide range of feedstock chemicals such as cycloalkanes and acyclic compounds as well as facilitating the late-stage functionalization of pharmaceuticals. We demonstrate further applications of our strategy with a three-component radical relay reaction and an enantioselective N-heterocyclic carbene (NHC) and cerium dual-catalyzed reaction.
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Affiliation(s)
- Jing Cao
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Joshua L Zhu
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Karl A Scheidt
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
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10
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Mandal T, Das S, Maji R, De Sarkar S. Visible-Light-Induced Hydrogen Atom Transfer En Route to Exocylic Alkenylation of Cyclic Ethers Enabled by Electron Donor-Acceptor Complex. Org Lett 2023; 25:7727-7732. [PMID: 37844302 DOI: 10.1021/acs.orglett.3c03099] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
An electron donor-acceptor (EDA)-triggered hydrogen atom transfer (HAT) process is developed for the efficient generation of an α-alkoxy radical from cyclic ethers to synthesize exocyclic alkenylated ethers with exclusive E-selectivity. A judiciously chosen donor-acceptor pair (DABCO and maleimide) serves as the desired HAT reagent under visible light irradiation without using any photocatalyst or peroxide. A wide variety of substrates were explored to demonstrate the diverse applicability and practical viability of this cross-dehydrogenative transformation. Detailed mechanistic studies revealed a radical reaction pathway under the oxidative environment.
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Affiliation(s)
- Tanumoy Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
| | - Sanju Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
| | - Rohan Maji
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
| | - Suman De Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India
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11
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Meger FS, Murphy JA. Recent Advances in C-H Functionalisation through Indirect Hydrogen Atom Transfer. Molecules 2023; 28:6127. [PMID: 37630379 PMCID: PMC10459052 DOI: 10.3390/molecules28166127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
The functionalisation of C-H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple synthetic equivalents for synthons. Hydrogen atom transfer (HAT) is a key method for forming alkyl radicals from C-H substrates. Classic reactions, including the Barton nitrite ester reaction and Hofmann-Löffler-Freytag reaction, among others, provided early examples of HAT. However, recent developments in photoredox catalysis and electrochemistry have made HAT a powerful synthetic tool capable of introducing a wide range of functional groups into C-H bonds. Moreover, greater mechanistic insights into HAT have stimulated the development of increasingly site-selective protocols. Site-selectivity can be achieved through the tuning of electron density at certain C-H bonds using additives, a judicious choice of HAT reagent, and a solvent system. Herein, we describe the latest methods for functionalizing C-H/Si-H/Ge-H bonds using indirect HAT between 2018-2023, as well as a critical discussion of new HAT reagents, mechanistic aspects, substrate scopes, and background contexts of the protocols.
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Affiliation(s)
- Filip S. Meger
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, 16 Avinguda dels Països Catalans, 43007 Tarragona, Catalonia, Spain
| | - John A. Murphy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UK
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