1
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Huang S, Chen X, Xu Z, Zeng X, Xiong B, Qiu X. Radical alkylation and protonation induced anti-Markovnikov hydroalkylation of unactivated olefins via cobalt catalysis. Chem Commun (Camb) 2024; 60:9258-9261. [PMID: 39119642 DOI: 10.1039/d4cc03136a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Although strategies of olefin hydroalkylation continue to emerge rapidly, the precise control of the regio- or chemoselectivity and the expansion of the reaction range are still challenges. Herein, a straightforward route for cobalt-catalyzed anti-Markovnikov hydroalkylation of unactivated olefins with alkyl iodides has been achieved. The developed reaction is compatible with oxa-, aza-, cyclo- and a series of other functional groups as well as the frameworks of some bioactive compounds. Mechanism studies confirm that an alkyl radical is involved and cobalt-alkyl insertion followed by protonation with water are possible pathways in this reaction.
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Affiliation(s)
- Shanshan Huang
- Nantong Key Laboratory of Small Molecular Drug Innovation, School of Pharmacy, Nantong University, 9 Seyuan Road, Nantong 226019, China.
| | - Xiaoyang Chen
- Nantong Key Laboratory of Small Molecular Drug Innovation, School of Pharmacy, Nantong University, 9 Seyuan Road, Nantong 226019, China.
| | - Zhangwenyi Xu
- Nantong Key Laboratory of Small Molecular Drug Innovation, School of Pharmacy, Nantong University, 9 Seyuan Road, Nantong 226019, China.
| | - Xiaobao Zeng
- Nantong Key Laboratory of Small Molecular Drug Innovation, School of Pharmacy, Nantong University, 9 Seyuan Road, Nantong 226019, China.
| | - Biao Xiong
- Nantong Key Laboratory of Small Molecular Drug Innovation, School of Pharmacy, Nantong University, 9 Seyuan Road, Nantong 226019, China.
| | - Xiaodong Qiu
- Nantong Key Laboratory of Small Molecular Drug Innovation, School of Pharmacy, Nantong University, 9 Seyuan Road, Nantong 226019, China.
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2
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Capaldo L, Wan T, Mulder R, Djossou J, Noël T. Visible light-induced halogen-atom transfer by N-heterocyclic carbene-ligated boryl radicals for diastereoselective C(sp 3)-C(sp 2) bond formation. Chem Sci 2024:d4sc02962c. [PMID: 39184300 PMCID: PMC11340342 DOI: 10.1039/d4sc02962c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Accepted: 08/07/2024] [Indexed: 08/27/2024] Open
Abstract
Photoinduced halogen-atom transfer (XAT) has rapidly emerged as a programmable approach to generate carbon-centered radical intermediates, mainly relying on silyl and α-aminoalkyl radicals as halogen abstractors. More recently, ligated boryl radicals have also been proposed as effective halogen abstractors under visible-light irradiation. In this study, we describe the use of this approach to enable C(sp3)-C(sp2) bond formation via radical addition of carbon-centered radicals generated via XAT onto chloroalkynes. Our mechanistic investigation reveals a complex interplay of highly reactive radical intermediates which, under optimized conditions, delivered the targeted vinyl chlorides in excellent yields and Z : E ratios. Finally, we demonstrated the synthetic value of these products in transition metal-based cross-coupling reactions.
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Affiliation(s)
- Luca Capaldo
- Flow Chemistry Group, Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
- Department of Chemistry, SynCat Lab, Life Sciences and Environmental Sustainability, University of Parma 43124 Parma Italy
| | - Ting Wan
- Flow Chemistry Group, Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
- The Research Center of Chiral Drugs, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine Shanghai 201203 China
| | - Robin Mulder
- Flow Chemistry Group, Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Jonas Djossou
- Flow Chemistry Group, Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Timothy Noël
- Flow Chemistry Group, Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
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3
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Wan T, Ciszewski ŁW, Ravelli D, Capaldo L. Photoinduced Intermolecular Radical Hydroalkylation of Olefins via Ligated Boryl Radicals-Mediated Halogen Atom Transfer. Org Lett 2024; 26:5839-5843. [PMID: 38950385 PMCID: PMC11250028 DOI: 10.1021/acs.orglett.4c02034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/21/2024] [Accepted: 06/26/2024] [Indexed: 07/03/2024]
Abstract
Light-mediated Halogen-Atom Transfer (XAT) has become a significant methodology in contemporary synthesis. Unlike α-aminoalkyl and silyl radicals, ligated boryl radicals (LBRs) have not been extensively explored as halogen atom abstractors. In this study, we introduce NHC-ligated boranes as optimal radical chain carriers for the intermolecular reductive radical hydroalkylation and hydroarylation of electron-deficient olefins by using direct UV-A light irradiation. DFT analysis allowed us to rationalize the critical role of the NHC ligand in facilitating efficient chain propagation.
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Affiliation(s)
- Ting Wan
- Flow
Chemistry Group, van’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- The
Research Center of Chiral Drugs, Innovation Research Institute of
Traditional Chinese Medicine, Shanghai University
of Traditional Chinese Medicine, Shanghai 201203, China
| | - Łukasz W. Ciszewski
- Flow
Chemistry Group, van’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Davide Ravelli
- PhotoGreen
Lab, Department of Chemistry, University
of Pavia, 27100 Pavia, Italy
| | - Luca Capaldo
- Flow
Chemistry Group, van’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- SynCat
Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
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4
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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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5
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Pan QJ, Miao YQ, Cao HJ, Liu Z, Chen X. Visible Light-Induced 1,2-Diphenyldisulfane-Mediated Defluoroborylation of Polyfluoroarenes. J Org Chem 2024; 89:5049-5059. [PMID: 38491018 DOI: 10.1021/acs.joc.4c00286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
A green and practical protocol of defluoroborylation of polyfluoroarenes with stable and readily accessible NHC-borane was developed, using 1,2-diphenyldisulfane as a hydrogen atom transfer (HAT) and single electron transfer (SET) reagent precursor under visible-light irradiation, leading to the concise formation of value-added fluorinated organoboron scaffolds. Mechanism studies revealed the method underwent a boryl radical addition reaction with polyfluoroarene, followed by successive single electron transfer pathways and defluorination of the C-F bond to offer the targeted product. This unprecedented platform relies on 1,2-diphenyldisulfane and base without using expensive photocatalysts, highlighting the methodology has promising application value to prepare borylated polyfluoroarene compounds.
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Affiliation(s)
- Qiao-Jing Pan
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yu-Qi Miao
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Hou-Ji Cao
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Zhenxing Liu
- College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xuenian Chen
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
- College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
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6
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Xu S, Zhang H, Xu J, Suo W, Lu CS, Tu D, Guo X, Poater J, Solà M, Yan H. Photoinduced Selective B-H Activation of nido-Carboranes. J Am Chem Soc 2024; 146:7791-7802. [PMID: 38461434 DOI: 10.1021/jacs.4c00550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
The development of new synthetic methods for B-H bond activation has been an important research area in boron cluster chemistry, which may provide opportunities to broaden the application scope of boron clusters. Herein, we present a new reaction strategy for the direct site-selective B-H functionalization of nido-carboranes initiated by photoinduced cage activation via a noncovalent cage···π interaction. As a result, the nido-carborane cage radical is generated through a single electron transfer from the 3D nido-carborane cage to a 2D photocatalyst upon irradiation with green light. The resulting transient nido-carborane cage radical could be directly probed by an advanced time-resolved EPR technique. In air, the subsequent transformations of the active nido-carborane cage radical have led to efficient and selective B-N, B-S, and B-Se couplings in the presence of N-heterocycles, imines, thioethers, thioamides, and selenium ethers. This protocol also facilitates both the late-stage modification of drugs and the synthesis of nido-carborane-based drug candidates for boron neutron capture therapy (BNCT).
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Affiliation(s)
- Shengwen Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hongjian Zhang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jingkai Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Weiqun Suo
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Chang-Sheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Deshuang Tu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xingwei Guo
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jordi Poater
- Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1-11, Barcelona 08028, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona 08010, Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany 69, Girona, Catalonia 17003, Spain
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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7
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Wei J, Du Z, Wang X, Ji C, Li L, You Y. Palladium-catalyzed enantioselective arylation of trichloro- or tri-/difluoroacetaldimine precursors. Chem Commun (Camb) 2024; 60:3303-3306. [PMID: 38426541 DOI: 10.1039/d4cc00022f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
A palladium-catalyzed asymmetric α-arylation of N-carbamoyl imine precursors containing CCl3, CF3 and CF2H is presented. This protocol provides facile access to a series of chiral α-aryl trichloroethylamines bearing various functional groups, with moderate to high yields (40-82% yield) and high enantioselectivity (80-99% ee).
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Affiliation(s)
- Jian Wei
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, Hefei 230009, P. R. China.
| | - Zhongjian Du
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, Hefei 230009, P. R. China.
| | - Xu Wang
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, Hefei 230009, P. R. China.
| | - Chenlei Ji
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, Hefei 230009, P. R. China.
| | - Longji Li
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, Hefei 230009, P. R. China.
- Department of Nuclear Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, P. R. China
| | - Yang'en You
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, Hefei 230009, P. R. China.
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8
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Guo X, Lin Z. Boryls, their compounds and reactivity: a structure and bonding perspective. Chem Sci 2024; 15:3060-3070. [PMID: 38425516 PMCID: PMC10901493 DOI: 10.1039/d3sc06864a] [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: 12/21/2023] [Accepted: 02/01/2024] [Indexed: 03/02/2024] Open
Abstract
Boryls and their compounds are important due to their diverse range of applications in the fields of materials science and catalysis. They are an integral part of boron chemistry, which has attracted tremendous research interest over the past few decades. In this perspective, we provide an in-depth analysis of the reaction chemistry of boryl compounds from a structure and bonding perspective. We discuss the reactivity of boryls in various transition metal complexes and diborane(4) compounds towards different substrate molecules, with a focus on their nucleophilic and electrophilic properties in various reaction processes. Additionally, we briefly discuss the reactivity of boryl radicals. Our analysis sheds new light on the unique properties of boryls and their potential for catalytic applications.
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Affiliation(s)
- Xueying Guo
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
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9
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Zhang X, Wei MY, Su JC, Liang C, Pan CX, Su GF, Mo DL. Synthesis of 4-(trichloromethyl)pyrido[2',1':3,4]pyrazino[2,1- b]quinazolinones through a cyclized dearomatization and trichloromethylation cascade strategy. Org Biomol Chem 2024; 22:1386-1390. [PMID: 38276964 DOI: 10.1039/d3ob02084c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
A variety of 4-(trichloromethyl)pyrido[2',1':3,4]pyrazino[2,1-b]quinazolinones were prepared in moderate to good yields with high regioselectivity through intramolecular 6-endo-dig cyclization and trichloromethylation of N3-alkynyl-2-pyridinyl-tethered quinazolinones in chloroform. Mechanistic studies revealed that chloroform might serve as a trichloromethyl anion precursor. Furthermore, the reaction could be easily performed on gram scales and an estrone-derived 4-(trichloromethyl)pyrido[2',1':3,4]pyrazino[2,1-b]quinazolinone was prepared over five steps. The present method features broad substrate scope, good functional group tolerance, new dearomatization of pyridine rings, and chloroform as the trichloromethylation reagent.
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Affiliation(s)
- Xu Zhang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
| | - Meng-Yan Wei
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
| | - Jun-Cheng Su
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
| | - Cui Liang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
| | - Cheng-Xue Pan
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
| | - Gui-Fa Su
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
| | - Dong-Liang Mo
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin, 541004, China.
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10
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Yue F, Ma H, Ding P, Song H, Liu Y, Wang Q. Formation of C-B, C-C, and C-X Bonds from Nonstabilized Aryl Radicals Generated from Diaryl Boryl Radicals. ACS CENTRAL SCIENCE 2023; 9:2268-2276. [PMID: 38161365 PMCID: PMC10755731 DOI: 10.1021/acscentsci.3c00993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/14/2023] [Accepted: 10/30/2023] [Indexed: 01/03/2024]
Abstract
With the development of organoboron chemistry, boron-centered radicals have become increasingly attractive. However, their synthetic applications remain limited in that they have been used only as substrates for addition reactions or as initiators for catalytic reactions. We have achieved a new reaction pathway in which tetraarylborate salts are used as precursors for aryl radicals via boron radicals, by introducing a simple activation reagent. In addition, we carried out a diverse array of transformations involving these aryl radical precursors, which allowed the construction of new C-B, C-C, and C-X bonds in the presence of visible light.
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Affiliation(s)
- Fuyang Yue
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Henan Ma
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Pengxuan Ding
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Hongjian Song
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Yuxiu Liu
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Qingmin Wang
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
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11
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Zhang ZQ, Wang CQ, Li LJ, Piper JL, Peng ZH, Ma JA, Zhang FG, Wu J. Programmable synthesis of difluorinated hydrocarbons from alkenes through a photocatalytic linchpin strategy. Chem Sci 2023; 14:11546-11553. [PMID: 37886092 PMCID: PMC10599468 DOI: 10.1039/d3sc03951j] [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: 07/31/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023] Open
Abstract
The introduction of difluoromethylene moieties into organic molecules has garnered significant attention due to their profound influence on the physicochemical and biological properties of compounds. Nonetheless, the existing approaches for accessing difluoroalkanes from readily available feedstock chemicals remain limited. In this study, we present an efficient and modular protocol for the synthesis of difluorinated compounds from alkenes, employing the readily accessible reagent, ClCF2SO2Na, as a versatile "difluoromethylene" linchpin. By means of an organophotoredox-catalysed hydrochlorodifluoromethylation of alkenes, followed by a ligated boryl radical-facilitated halogen atom transfer (XAT) process, we have successfully obtained various difluorinated compounds, including gem-difluoroalkanes, gem-difluoroalkenes, difluoromethyl alkanes, and difluoromethyl alkenes, with satisfactory yields. The practical utility of this linchpin strategy has been demonstrated through the successful preparation of CF2-linked derivatives of complex drugs and natural products. This method opens up new avenues for the synthesis of structurally diverse difluorinated hydrocarbons and highlights the utility of ligated boryl radicals in organofluorine chemistry.
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Affiliation(s)
- Zhi-Qi Zhang
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University Tianjin 300072 P. R. China
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Cheng-Qiang Wang
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Long-Ji Li
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Jared L Piper
- Pfizer Worldwide Research and Development Medicine Eastern Point Rd, Groton CT 06340 USA
| | - Zhi-Hui Peng
- Pfizer Worldwide Research and Development Medicine Eastern Point Rd, Groton CT 06340 USA
| | - Jun-An Ma
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University Tianjin 300072 P. R. China
| | - Fa-Guang Zhang
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University Tianjin 300072 P. R. China
| | - Jie Wu
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
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12
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Chung KY, Page ZA. Boron-Methylated Dipyrromethene as a Green Light Activated Type I Photoinitiator for Rapid Radical Polymerizations. J Am Chem Soc 2023; 145:17912-17918. [PMID: 37540781 DOI: 10.1021/jacs.3c05373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
Unimolecular (Type I) radical photoinitiators (PIs) have transformed the chemical manufacturing industry by enabling (stereo)lithography for microelectronics and emergent 3D printing technologies. However, the reliance on high energy UV-violet light (≤420 nm) restricts the end-use applications. Herein, boron-methylated dipyrromethene (methylated-BODIPY) is shown to act as a highly efficient Type I radical PI upon irradiation with low energy green light. Using a low intensity (∼4 mW/cm2) light emitting diode centered at 530 nm and a low PI concentration (0.3 mol %), acrylic-based resins were polymerized to maximum conversion in ∼10 s. Under equivalent conditions (wavelength, intensity, and PI concentration), state-of-the-art visible light PIs Ivocerin and Irgacure 784 show no appreciable polymerization. Spectroscopic characterization suggests that homolytic β-scission at the boron-carbon bond results in radical formation, which is further facilitated by accessing long-lived triplet excited states through installment of bromine. Alkylated-BODIPYs represent a new modular visible light PI platform with exciting potential to enable next generation manufacturing and biomedical applications where a spectrally discrete, low energy, and thus benign light source is required.
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Affiliation(s)
- Kun-You Chung
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zachariah A Page
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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Ren H, Zhang P, Xu J, Ma W, Tu D, Lu CS, Yan H. Direct B-H Functionalization of Icosahedral Carboranes via Hydrogen Atom Transfer. J Am Chem Soc 2023; 145:7638-7647. [PMID: 36946888 DOI: 10.1021/jacs.3c01314] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The efficient and selective functionalization of icosahedral carboranes (C2B10H12) at the boron vertexes is a long-standing challenge owing to the presence of 10 inert B-H bonds in a similar chemical environment. Herein, we report a new reaction paradigm for direct B-H functionalization of icosahedral carboranes via B-H homolysis enabled by a nitrogen-centered radical-mediated hydrogen atom transfer (HAT) strategy. Both the HAT process of the carborane B-H bond and the resulting boron-centered carboranyl radical intermediate have been confirmed experimentally. The reaction occurs at the most electron-rich boron vertex with the lowest B-H bond dissociation energy (BDE). Using this strategy, diverse carborane derivatization, including thiolation, selenation, alkynylation, alkenylation, cyanation, and halogenation, have been achieved in satisfactory yields under a photoinitiated condition in a metal-free and redox-neutral fashion. Moreover, the synthetic utility of the current protocol was also demonstrated by both the scale-up reaction and the construction of carborane-based functional molecules. Therefore, this methodology opens a radical pathway to carborane functionalization, which is distinct from the B-H heterolytic mechanism in the traditional strategies.
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Affiliation(s)
- Hongyuan Ren
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Ping Zhang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jingkai Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wenli Ma
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Deshuang Tu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chang-Sheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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Peng TY, Zhang FL, Wang YF. Lewis Base-Boryl Radicals Enabled Borylation Reactions and Selective Activation of Carbon-Heteroatom Bonds. Acc Chem Res 2023; 56:169-186. [PMID: 36571794 DOI: 10.1021/acs.accounts.2c00752] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
ConspectusThe past decades have witnessed tremendous progress on radical reactions. However, in comparison with carbon, nitrogen, oxygen, and other main group element centered radicals, the synthetic chemistry of boron centered radicals was less studied, mainly due to the high electron-deficiency and instability of such 3-center-5-electron species. In the 1980s, Roberts and co-workers found that the coordination of a Lewis base (amines or phosphines) with the boron center could form 4-center-7-electron boryl radicals (Lewis base-boryl radicals, LBRs) that are found to be more stable. However, only limited synthetic applications were developed. In 2008, Curran and co-workers achieved a breakthrough with the discovery of N-heterocyclic carbene (NHC) boryl radicals, which could enable a range of radical reduction and polymerization reactions. Despite these exciting findings, more powerful and valuable synthetic applications of LBRs would be expected, given that the structures and reactivities of LBRs could be easily modulated, which would provide ample opportunities to discover new reactions. In this Account, a summary of our key contributions in LBR-enabled radical borylation reactions and selective activation of inert carbon-heteroatom bonds will be presented.Organoboron compounds have shown versatile applications in chemical society, and their syntheses rely principally on ionic borylation reactions. The development of mechanistically different radical borylation reactions allows synthesizing products that are inaccessible by traditional methods. For this purpose, we progressively developed a series of NHC-boryl radical mediated chemo-, regio-, and stereoselective radical borylation reactions of alkenes and alkynes, by which a wide variety of structurally diverse organoboron molecules were successfully prepared. The synthetic utility of these borylated products was also demonstrated. Furthermore, we disclosed a photoredox protocol for oxidative generation of NHC-boryl radicals, which enabled useful defluoroborylation and arylboration reactions.Selective bond activation is an ideal way to convert simple starting materials to value-added products, while the cleavage of inert chemical bonds, in particular the chemoselectivity control when multiple identical bonds are present in similar chemical environments, remains a long-standing challenge. We envisaged that finely tuning the properties of LBRs might provide a new solution to address this challenge. Recently, we disclosed a 4-dimethylaminopyridine (DMAP)-boryl radical promoted sequential C-F bond functionalization of trifluoroacetic acid derivatives, in which the α-C-F bonds were selectively snipped via a spin-center shift mechanism. This strategy enables facile conversion of abundantly available trifluoroacetic acid to highly valuable mono- and difluorinated molecules. Encouraged by this finding, we further developed a boryl radical enabled three-step sequence to construct all-carbon quaternary centers from a range of trichloromethyl groups, where the three C-Cl bonds were selectively cleaved by the rational choice of suitable boryl radical precursors in each step. Furthermore, a boryl radical promoted dehydroxylative alkylation of α-hydroxy carboxylic acid derivatives was achieved, allowing for the efficient conversion of some biomass platform molecules to high value products.
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Affiliation(s)
- Tian-Yu Peng
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, 230026 Anhui, China
| | - Feng-Lian Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, 230026 Anhui, China
| | - Yi-Feng Wang
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, 230026 Anhui, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China
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He X, Ye K. Stepwise Construction of All-Carbon Quaternary Centers Starting from Activated Trichloromethyl Group in Three Steps. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202200060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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