1
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Zhang J, Wu J. Recent progress in asymmetric radical reactions enabled by chiral iron catalysts. Chem Commun (Camb) 2024. [PMID: 39380541 DOI: 10.1039/d4cc03047h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
Abstract
Transition-metal-catalyzed radical asymmetric reactions offer a versatile and effective platform for accessing chiral organic molecules with high enantiopurity. Given that iron is the most abundant and less toxic transition metalic element available, the application of iron catalysts is considered to be a more sustainable and attractive approach. Over the last decade, several exciting and notable achievements have been witnessed. In this highlight, we aim to provide an overview of the progress in ligand-enabled iron-catalyzed asymmetric radical reactions, with an emphasis on the reaction mechanisms.
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Affiliation(s)
- Jun Zhang
- School of Pharmaceutical and Chemical Engineering & Institute for Advanced Studies, Taizhou University, 1139 Shifu Avenue, Taizhou 318000, China.
| | - Jie Wu
- School of Pharmaceutical and Chemical Engineering & Institute for Advanced Studies, Taizhou University, 1139 Shifu Avenue, Taizhou 318000, China.
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China
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2
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Wu WQ, Xie PP, Wang LY, Gou BB, Lin Y, Hu LW, Zheng C, You SL, Shi H. Chiral Bis(binaphthyl) Cyclopentadienyl Ligands for Rhodium-Catalyzed Desymmetrization of Diarylmethanes via Selective Arene Coordination. J Am Chem Soc 2024; 146:26630-26638. [PMID: 39293091 DOI: 10.1021/jacs.4c10876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2024]
Abstract
Owing to substantial advances in the past several decades, transition-metal-catalyzed asymmetric reactions have garnered considerable attention as pivotal methods for constructing chiral molecules from abundant, readily available achiral counterparts. These advances are largely attributed to the development of chiral ligands that control stereochemistry through steric repulsion and other noncovalent interactions between the ligands and functional groups or prochiral centers on the substrates. However, stereocontrol weakens dramatically with increasing distance between the reaction site and the functional group or prochiral center. Herein, we report a symphonic strategy for remote stereocontrol of Rh(III)-catalyzed asymmetric benzylic C-H bond addition reactions of diarylmethanes in which the two aryl motifs differ at the meta and/or para position. Specifically, catalysts bearing a new type of chiral cyclopentadienyl (Cp) ligand differentiate between the two aromatic rings of the diarylmethane by arene-selective η6 coordination, setting up an opportunity for ligand-controlled stereoselective benzylic deprotonation and subsequent stereoselective addition to the 1,1-bis(arylsulfonyl)ethylene.
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Affiliation(s)
- Wen-Qiang Wu
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang Province 310058, China
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang Province 310030, China
| | - Pei-Pei Xie
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Le-Yao Wang
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang Province 310030, China
| | - Bo-Bo Gou
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yunzhi Lin
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang Province 310030, China
| | - Li-Wei Hu
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang Province 310030, China
| | - Chao Zheng
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shu-Li You
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hang Shi
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang Province 310030, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang Province 310024, China
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3
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Zhou J, Zhao Z, Kiyono T, Matsuno A, Escorihuela J, Shibata N. A silylboronate-mediated strategy for cross-coupling of alkyl fluorides with aryl alkanes: mechanistic insights and scope expansion. Chem Sci 2024:d4sc04357j. [PMID: 39364067 PMCID: PMC11446385 DOI: 10.1039/d4sc04357j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Accepted: 09/23/2024] [Indexed: 10/05/2024] Open
Abstract
The construction of C(sp3)-C(sp3) bonds is pivotal in organic synthesis; however, traditional methods involving alkyl halides are often limited by substrate tolerance and bond dissociation energies, particularly with alkyl fluorides. Herein, we report a silylboronate-mediated cross-coupling strategy that circumvents these challenges, enabling the efficient formation of C(sp3)-C(sp3) bonds between alkyl fluorides and aryl alkanes under mild conditions. Various alkyl fluorides have also been effectively utilized, demonstrating the versatility and broad applicability of this approach. The use of diglyme is critical for this transformation which encapsulates potassium cations and enhances the reaction efficiency. Conventional alkyl halides, including chlorides, bromides, and iodides, are also suitable for this transformation. Density functional theory (DFT) calculations were conducted on the silylboronate-mediated coupling reactions for the first time. Interestingly, while experimental results suggest a radical mechanism, DFT calculations indicate a preference for an ionic pathway.
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Affiliation(s)
- Jun Zhou
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
| | - Zhengyu Zhao
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
| | - Tatsuki Kiyono
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
| | - Ayaka Matsuno
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
| | - Jorge Escorihuela
- Departamento de Química Orgánica, Universitat de València Avda. Vicente Andrés Estellés s/n, Burjassot 46100 Valencia Spain
| | - Norio Shibata
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
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4
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Zuo L, Yu F, Zhao S, Wang W, Wang S. Copper-Catalyzed, Intramolecular Amination of Unactivated C(sp 3)-H Bonds through Radical Relay. J Org Chem 2024; 89:13077-13084. [PMID: 39208327 DOI: 10.1021/acs.joc.4c01163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Although copper-catalyzed amination of activated C(sp3)-H bonds through radical relay has been developed, amination of unactivated C(sp3)-H bonds is rare. Herein, copper-catalyzed intramolecular amination of remote unactivated C(sp3)-H bonds is reported. The reaction is conducted in a mild and effective manner with moderate to good yields, demonstrating broad tolerance toward various functional groups and exhibiting complete regio- and chemoselectivities. This innovation supplies novel synthetic pathways for the construction of saturated nitrogenated heterocycles.
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Affiliation(s)
- Liyan Zuo
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Fan Yu
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Shuai Zhao
- Qingdao Zhongda Agritech Co., Ltd., Building 1, No. 368 Hedong Road, High-tech Zone, Qingdao, Shandong 266100, P. R. China
| | - Wengui Wang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Shoufeng Wang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
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5
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Chen TA, Staples RJ, Warren TH. Copper catalyzed benzylic sp 3 C-H alkenylation. Chem Sci 2024:d4sc03430a. [PMID: 39391381 PMCID: PMC11459437 DOI: 10.1039/d4sc03430a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Accepted: 09/15/2024] [Indexed: 10/12/2024] Open
Abstract
The prenyl group is present in numerous biologically active small molecule drugs and natural products. We introduce benzylic C-H alkenylation of substrates Ar-CH3 with alkenylboronic esters (CH2)3O2B-CH[double bond, length as m-dash]CMe2 as a pathway to form prenyl functionalized arenes Ar-CH2CH[double bond, length as m-dash]CMe2. Mechanistic studies of this radical relay catalytic protocol reveal diverse reactivity pathways exhibited by the copper(ii) alkenyl intermediate [CuII]-CH[double bond, length as m-dash]CMe2 that involve radical capture, bimolecular C-C bond formation, and hydrogen atom transfer (HAT).
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Affiliation(s)
- Ting-An Chen
- Department of Chemistry, Georgetown University Washington D.C. 20057 USA
- Department of Chemistry, Michigan State University East Lansing Michigan 48824 USA
| | - Richard J Staples
- Department of Chemistry, Michigan State University East Lansing Michigan 48824 USA
| | - Timothy H Warren
- Department of Chemistry, Michigan State University East Lansing Michigan 48824 USA
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6
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Tao Y, Ma W, Sun R, Huang C, Lu Q. Asymmetric Paired Electrolysis: Enantioselective Alkylation of Sulfonylimines via C(sp 3)-H Functionalization. Angew Chem Int Ed Engl 2024; 63:e202409222. [PMID: 38958225 DOI: 10.1002/anie.202409222] [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: 05/15/2024] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 07/04/2024]
Abstract
Enantioselective transformation of ubiquitous C(sp3)-H bonds into three-dimensional chiral scaffolds is of longstanding interest to synthetic chemists. Herein, an asymmetric paired electrolysis enables a highly efficient and sustainable approach to the enantioselective alkylation of sulfonylimines via C(sp3)-H functionalization. In this protocol, anodic oxidation for benzylic radical formation and Lewis acid-catalyzed sulfonylimine reduction on the cathode were seamlessly cross-coupled (up to 88 % yield). Enantioenriched chiral amines containing a tetrasubstituted carbon stereocenter are accessed with high enantioselectivity (up to 96 % ee). Mechanistic studies suggest that the amine generated in situ could serve as a base to deprotonate phenols and decrease the oxidation potential of the reaction, allowing phenols with lower potentials to be preferentially oxidized.
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Affiliation(s)
- Yongsheng Tao
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Wan Ma
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Rui Sun
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Cheng Huang
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Qingquan Lu
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
- Wuhan University Shenzhen Research Institute, Shenzhen, 518000, P. R. China
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7
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Zhang Q, Liu T, Wu L, Zhou CY, Wang C. Defunctionalization Enabled by Intramolecular Radical Aromatic Ipso Substitution. Org Lett 2024; 26:7744-7750. [PMID: 39235307 DOI: 10.1021/acs.orglett.4c02910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
A chemoselective and regioselective copper-promoted defunctionalization procedure has been developed, enabling the rapid construction of various N-polyheterocycles. Initial mechanistic studies reveal that a single-electron transfer radical process is potentially involved.
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Affiliation(s)
- Qijing Zhang
- College of Chemistry and Materials Science, Jinan University, Guangzhou, Guangdong 511443, China
| | - Tinglan Liu
- College of Chemistry and Materials Science, Jinan University, Guangzhou, Guangdong 511443, China
| | - Lili Wu
- College of Chemistry and Materials Science, Jinan University, Guangzhou, Guangdong 511443, China
| | - Cong-Ying Zhou
- College of Chemistry and Materials Science, Jinan University, Guangzhou, Guangdong 511443, China
| | - Chengming Wang
- College of Chemistry and Materials Science, Jinan University, Guangzhou, Guangdong 511443, China
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8
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Wang X, He J, Wang YN, Zhao Z, Jiang K, Yang W, Zhang T, Jia S, Zhong K, Niu L, Lan Y. Strategies and Mechanisms of First-Row Transition Metal-Regulated Radical C-H Functionalization. Chem Rev 2024; 124:10192-10280. [PMID: 39115179 DOI: 10.1021/acs.chemrev.4c00188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Radical C-H functionalization represents a useful means of streamlining synthetic routes by avoiding substrate preactivation and allowing access to target molecules in fewer steps. The first-row transition metals (Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) are Earth-abundant and can be employed to regulate radical C-H functionalization. The use of such metals is desirable because of the diverse interaction modes between first-row transition metal complexes and radical species including radical addition to the metal center, radical addition to the ligand of metal complexes, radical substitution of the metal complexes, single-electron transfer between radicals and metal complexes, hydrogen atom transfer between radicals and metal complexes, and noncovalent interaction between the radicals and metal complexes. Such interactions could improve the reactivity, diversity, and selectivity of radical transformations to allow for more challenging radical C-H functionalization reactions. This review examines the achievements in this promising area over the past decade, with a focus on the state-of-the-art while also discussing existing limitations and the enormous potential of high-value radical C-H functionalization regulated by these metals. The aim is to provide the reader with a detailed account of the strategies and mechanisms associated with such functionalization.
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Affiliation(s)
- Xinghua Wang
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Jing He
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Ya-Nan Wang
- School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Chemical Theory and Mechanism, Chongqing University, Chongqing 401331, P. R. China
| | - Zhenyan Zhao
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Kui Jiang
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Wei Yang
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Tao Zhang
- Institute of Intelligent Innovation, Henan Academy of Sciences, Zhengzhou, Henan 451162, P. R. China
| | - Shiqi Jia
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Kangbao Zhong
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Henan Normal University, Xinxiang, Henan 453007, P. R. China
| | - Linbin Niu
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Henan Normal University, Xinxiang, Henan 453007, P. R. China
| | - Yu Lan
- College of Chemistry, and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
- School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Chemical Theory and Mechanism, Chongqing University, Chongqing 401331, P. R. China
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Henan Normal University, Xinxiang, Henan 453007, P. R. China
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9
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Cheng Z, Zhang J, Li C, Li X, Chen P, Liu G. Copper-Catalyzed sp 2 C-H Arylation and Alkynylation of Allenes via Hydrogen Atom Abstraction. J Am Chem Soc 2024; 146:24689-24698. [PMID: 39167590 DOI: 10.1021/jacs.4c09324] [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
Development of methods for the sp2 C-H transformations of allenes has received much attention, and it presents a powerful tool for the synthesis of complicated allene-containing bioactive molecules. With a copper-catalyzed radical relay, sp2 allenic C-H arylation and alkynylation were established herein, using various aryl boronic acids and trimethoxysilyl-substituted alkynes as carbon nucleophiles and using electrophilic N-F reagents as nitrogen-centered radical precursors. These methods featured excellent site selectivity to deliver fully substituted allenes efficiently. Moreover, with silyl-substituted allenes as substrates, a subsequent dual sp2 C-H functionalization process was established as well, which allowed for the divergent synthesis of multifunctionalized allenes, significantly expanding their chemical spaces.
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Affiliation(s)
- Zhongming Cheng
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jiajun Zhang
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Can Li
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Xiang Li
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Pinhong Chen
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Guosheng Liu
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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10
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Weng Y, Jin Y, Wu J, Leng X, Lou X, Geng F, Hu B, Wu B, Shen Q. Oxidative Substitution of Organocopper(II) by a Carbon-Centered Radical. J Am Chem Soc 2024; 146:23555-23565. [PMID: 39116098 DOI: 10.1021/jacs.4c07552] [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
Copper-catalyzed coupling reactions of alkyl halides are believed to prominently involve copper(II) species and alkyl radicals as pivotal intermediates, with their exact interaction mechanism being the subject of considerable debate. In this study, a visible light-responsive fluoroalkylcopper(III) complex, [(terpy)Cu(CF3)2(CH2CO2tBu)] Trans-1, was designed to explore the mechanism. Upon exposure to blue LED irradiation, Trans-1 undergoes copper-carbon bond homolysis, generating Cu(II) species and carbon-centered radicals, where the carbon-centered radical then recombines with the Cu(II) intermediate, resulting in the formation of Cis-1, the Cis isomer of Trans-1. Beyond this, a well-defined fluoroalkylcopper(II) intermediate ligated with a sterically hindered ligand was isolated and underwent full characterization and electronic structure studies. The collective experimental, computational, and spectroscopic findings in this work strongly suggest that organocopper(II) engages with carbon-centered radicals via an "oxidative substitution" mechanism, which is likely the operational pathway for copper-catalyzed C-H bond trifluoromethylation reactions.
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Affiliation(s)
- Yuecheng Weng
- State Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
| | - Yuxuan Jin
- State Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
| | - Jian Wu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
| | - Xuebing Leng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
| | - Xiaobing Lou
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China
| | - Fushan Geng
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China
| | - Bingwen Hu
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China
| | - Botao Wu
- State Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
| | - Qilong Shen
- State Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
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11
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Zhan YF, Chen JM, Sheng XX, Qiu CY, Jiang Y, Yang S, Chen M. Photoinduced copper catalyzed nitrogen-to-alkyl radical relay Sonogashira-type coupling of o-alkylbenzamides with alkynes. Chem Commun (Camb) 2024; 60:7906-7909. [PMID: 38979947 DOI: 10.1039/d4cc02861a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
This report describes a copper-catalyzed, photoinduced N-to-alkyl radical relay Sonogashira-type reactions at benzylic sites in o-alkylbenzamides with alkynes. The process employs an N-to-alkyl radical mechanism, initiated through the copper-catalyzed reductive generation of nitrogen radicals. Radical translocation is facilitated by a 1,5-hydrogen atom transfer (1,5-HAT), leading to the formation of translocated carbon radicals. These radicals are then subjected to copper-catalyzed alkynylation. The methodology exhibits broad sub-strate scope and applicability to the synthesis of complex natural products.
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Affiliation(s)
- Yan-Fang Zhan
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
| | - Jia-Ming Chen
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
| | - Xia-Xin Sheng
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
| | - Chao-Ying Qiu
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
| | - Yan Jiang
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
| | - Sen Yang
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
| | - Ming Chen
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Chang-zhou University, Changzhou, 213164, China.
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12
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Atkins AP, Dean AC, Lennox AJJ. Benzylic C(sp 3)-H fluorination. Beilstein J Org Chem 2024; 20:1527-1547. [PMID: 39015617 PMCID: PMC11250007 DOI: 10.3762/bjoc.20.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/26/2024] [Indexed: 07/18/2024] Open
Abstract
The selective fluorination of C(sp3)-H bonds is an attractive target, particularly for pharmaceutical and agrochemical applications. Consequently, over recent years much attention has been focused on C(sp3)-H fluorination, and several methods that are selective for benzylic C-H bonds have been reported. These protocols operate via several distinct mechanistic pathways and involve a variety of fluorine sources with distinct reactivity profiles. This review aims to give context to these transformations and strategies, highlighting the different tactics to achieve fluorination of benzylic C-H bonds.
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Affiliation(s)
| | - Alice C Dean
- University of Bristol, School of Chemistry, Bristol, BS8 1TS, U.K.
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13
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Tang MP, Zhu L, Deng Y, Shi YX, Kin-Man Lai S, Mo X, Pang XY, Liu C, Jiang W, Tse ECM, Au-Yeung HY. Water and Air Stable Copper(I) Complexes of Tetracationic Catenane Ligands for Oxidative C-C Cross-Coupling. Angew Chem Int Ed Engl 2024; 63:e202405971. [PMID: 38661248 DOI: 10.1002/anie.202405971] [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: 03/28/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 04/26/2024]
Abstract
Aqueous soluble and stable Cu(I) molecular catalysts featuring a catenane ligand composed of two dicationic, mutually repelling but mechanically interlocked macrocycles are reported. The ligand interlocking not only fine-tunes the coordination sphere and kinetically stabilizes the Cu(I) against air oxidation and disproportionation, but also buries the hydrophobic portions of the ligands and prevents their dissociation which are necessary for their good water solubility and a sustained activity. These catenane Cu(I) complexes can catalyze the oxidative C-C coupling of indoles and tetrahydroisoquinolines in water, using H2O2 as a green oxidant with a good substrate scope. The successful use of catenane ligands in exploiting aqueous Cu(I) catalysis thus highlights the many unexplored potential of mechanical bond as a design element for exploring transition metal catalysis under challenging conditions.
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Affiliation(s)
- Man Pang Tang
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Lihui Zhu
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
- State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Yulin Deng
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Yi-Xiang Shi
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Samuel Kin-Man Lai
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Xiaoyong Mo
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Xin-Yu Pang
- Department of Chemistry, South University of Science and Technology of China, Xueyuan Blvd 1088, Shenzhen, 518055, P. R. China
| | - Chunyu Liu
- Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi, 100083, P. R. China
| | - Wei Jiang
- Department of Chemistry, South University of Science and Technology of China, Xueyuan Blvd 1088, Shenzhen, 518055, P. R. China
| | - Edmund Chun Ming Tse
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
- CAS-HKU Joint Laboratory on New Materials, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Ho Yu Au-Yeung
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
- State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
- CAS-HKU Joint Laboratory on New Materials, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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14
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Zhuang Z, Sheng T, Qiao JX, Yeung KS, Yu JQ. Versatile Copper-Catalyzed γ-C(sp 3)-H Lactonization of Aliphatic Acids. J Am Chem Soc 2024; 146:17311-17317. [PMID: 38867480 DOI: 10.1021/jacs.4c04043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Site-selective C(sp3)-H oxidation is of great importance in organic synthesis and drug discovery. γ-C(sp3)-H lactonization of free carboxylic acids provides the most straightforward means to prepare biologically important lactone scaffolds from abundant and inexpensive carboxylic acids; however, a versatile catalyst for this transformation with a broad substrate scope remains elusive. Herein, we report a simple yet broadly applicable and scalable γ-lactonization reaction of free aliphatic acids enabled by a copper catalyst in combination with inexpensive Selectfluor as the oxidant. This lactonization reaction exhibits compatibility with tertiary, benzylic, allylic, methylene, and primary γ-C-H bonds, affording access to a wide range of structurally diverse lactones such as spiro, fused, and bridged lactones. Notably, exclusive γ-methylene C-H lactonization of cycloalkane carboxylic acids and cycloalkane acetic acids was observed, giving either fused or bridged γ-lactones that are difficult to access by other methods. δ-C-H lactonization was only favored in the presence of tertiary δ-C-H bonds. The synthetic utility of this methodology was demonstrated by the late-stage functionalization of amino acids, drug molecules, and natural products, as well as a two-step total synthesis of (iso)mintlactones (the shortest synthesis reported to date).
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Affiliation(s)
- Zhe Zhuang
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Tao Sheng
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jennifer X Qiao
- Small Molecule Drug Discovery, Bristol Myers Squibb Research and Early Development, P.O. Box 4000, Princeton, New Jersey 08543, United States
| | - Kap-Sun Yeung
- Small Molecule Drug Discovery, Bristol Myers Squibb Research and Early Development, 100 Binney Street, Cambridge, Massachusetts 02142, United States
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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15
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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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16
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Zhang J, Huan XD, Wang X, Li GQ, Xiao WJ, Chen JR. Recent advances in C(sp 3)-N bond formation via metallaphoto-redox catalysis. Chem Commun (Camb) 2024; 60:6340-6361. [PMID: 38832416 DOI: 10.1039/d4cc01969e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The C(sp3)-N bond is ubiquitous in natural products, pharmaceuticals, biologically active molecules and functional materials. Consequently, the development of practical and efficient methods for C(sp3)-N bond formation has attracted more and more attention. Compared to the conventional ionic pathway-based thermal methods, photochemical processes that proceed through radical mechanisms by merging photoredox and transition-metal catalyses have emerged as powerful and alternative tools for C(sp3)-N bond formation. In this review, recent advances in the burgeoning field of C(sp3)-N bond formation via metallaphotoredox catalysis have been highlighted. The contents of this review are categorized according to the transition metals used (copper, nickel, cobalt, palladium, and iron) together with photocatalysis. Emphasis is placed on methodology achievements and mechanistic insight, aiming to inspire chemists to invent more efficient radical-involved C(sp3)-N bond-forming reactions.
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Affiliation(s)
- Juan Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Xiao-Die Huan
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
| | - Xin Wang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Guo-Qing Li
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
| | - Wen-Jing Xiao
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
| | - Jia-Rong Chen
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
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17
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Gao X, He H, Miao K, Zhang L, Ni SF, Li M, Guo W. Electrochemical Allylic C(sp 3)-H Isothiocyanation via [3,3]-Sigmatropic Rearrangement. Org Lett 2024; 26:4554-4559. [PMID: 38767297 DOI: 10.1021/acs.orglett.4c01463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The direct allylic C(sp3)-H functionalization provides a straightforward protocol for the synthesis of valuable molecules. We report herein the first chemo- and site-selective method for allylic C(sp3)-H isothiocyanation of various internal alkenes under mild electrochemical conditions. This method exhibits broad functional group tolerance and excellent selectivity and can be applied for late-stage isothiocyanation of bioactive molecules. Combined experimental and computational studies indicate that the reaction proceeds via an unexpected [3,3]-sigmatropic rearrangement.
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Affiliation(s)
- Xuezhuang Gao
- College of Chemistry & Molecular Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, 266042 Qingdao, P. R. China
| | - Hui He
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong, Shantou University, Shantou, 515063 Guangdong, P. R. China
| | - Kaili Miao
- College of Chemistry & Molecular Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, 266042 Qingdao, P. R. China
| | - Linbao Zhang
- College of Chemistry & Molecular Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, 266042 Qingdao, P. R. China
| | - Shao-Fei Ni
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong, Shantou University, Shantou, 515063 Guangdong, P. R. China
| | - Ming Li
- College of Chemistry & Molecular Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, 266042 Qingdao, P. R. China
| | - Weisi Guo
- College of Chemistry & Molecular Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, 266042 Qingdao, P. R. China
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18
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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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19
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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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20
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Golden DL, Flynn KM, Aikonen S, Hanneman CM, Kalyani D, Krska SW, Paton RS, Stahl SS. Radical Chlorination of Non-Resonant Heterobenzylic C-H Bonds and High-Throughput Diversification of Heterocycles. Chem 2024; 10:1593-1605. [PMID: 39108591 PMCID: PMC11299866 DOI: 10.1016/j.chempr.2024.04.001] [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] [Indexed: 08/10/2024]
Abstract
Site-selective functionalization of the heterobenzylic C(sp3)-H bonds of pyridines and related heteroaromatic compounds presents challenges associated with the basic nitrogen atom and the variable reactivity among different positions on the heteroaromatic ring. Methods for functionalization of 2- and 4-alkylpyridines are increasingly available through polar pathways that leverage resonance stabilization of charge build-up at these positions. In contrast, functionalization of 3-alkylpyridines is largely inaccessible. Here, we report a photochemically promoted method for chlorination of non-resonant heterobenzylic C(sp3)-H sites in 3-alkylpyridines and related alkylheteroaromatics. Density functional theory calculations show that the optimal reactivity reflects a balance between the energetics of the two radical-chain propagation steps, with the preferred reagent consisting of an N-chlorosulfonamide. The operationally simple chlorination protocol enables access to heterobenzylic chlorides which serve as versatile intermediates in C-H cross-coupling reactions between heteroaromatic building blocks and diverse oxidatively sensitive nucleophiles using high-throughput experimentation.
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Affiliation(s)
- Dung L. Golden
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Present address: Chemical Process Development, Bristol Myers Squibb, 556 Morris Avenue, Summit, New Jersey 07901, United States
| | - Kaitlyn M. Flynn
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Present address: Drug Substance Development Chemistry, GSK, 1250 Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Santeri Aikonen
- Department of Chemistry, Colorado State University, 1301 Center Avenue, Ft. Collins, Colorado 80523, United States
- Present address: In Silico Discovery, Johnson & Johnson Innovative Medicine, 1400 McKean Road, Spring House, Pennsylvania 19477, United States
| | - Christopher M. Hanneman
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Dipannita Kalyani
- Discovery Chemistry, Merck & Co., Inc., 126 East Lincoln Ave., Rahway, New Jersey 07065, United States
| | - Shane W. Krska
- Discovery Chemistry, Merck & Co., Inc., 126 East Lincoln Ave., Rahway, New Jersey 07065, United States
| | - Robert S. Paton
- Department of Chemistry, Colorado State University, 1301 Center Avenue, Ft. Collins, Colorado 80523, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Lead contact
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21
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Borrel J, Waser J. SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes. Beilstein J Org Chem 2024; 20:701-713. [PMID: 38590536 PMCID: PMC10999984 DOI: 10.3762/bjoc.20.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 03/21/2024] [Indexed: 04/10/2024] Open
Abstract
We report the detailed background for the discovery and development of the synthesis of homopropargylic azides by the azido-alkynylation of alkenes. Initially, a strategy involving SOMOphilic alkynes was adopted, but only resulted in a 29% yield of the desired product. By switching to a radical-polar crossover approach and after optimization, a high yield (72%) of the homopropargylic azide was reached. Full insights are given about the factors that were essential for the success of the optimization process.
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Affiliation(s)
- Julien Borrel
- Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH 4306, 1015 Lausanne, Switzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH 4306, 1015 Lausanne, Switzerland
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22
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Wang G, Liu Y, Zhang X, Zong X, Zhang X, Zheng K, Qu D, An L, Qi X, Sun Z. Mechanistic Investigation into Single-Electron Oxidative Addition of Single-Atom Cu(I)-N 4 Site: Revealing the Cu(I)-Cu(II)-Cu(I) Catalytic Cycle in Photochemical Hydrophosphinylation. J Am Chem Soc 2024; 146:8668-8676. [PMID: 38498937 DOI: 10.1021/jacs.4c01023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Understanding the valency and structural variations of metal centers during reactions is important for mechanistic studies of single-atom catalysis, which could be beneficial for optimizing reactions and designing new protocols. Herein, we precisely developed a single-atom Cu(I)-N4 site catalyst via a photoinduced ligand exchange (PILE) strategy. The low-valent and electron-rich copper species could catalyze hydrophosphinylation via a novel single-electron oxidative addition (OA) pathway under light irradiation, which could considerably decrease the energy barrier compared with the well-known hydrogen atom transfer (HAT) and single electron transfer (SET) processes. The Cu(I)-Cu(II)-Cu(I) catalytic cycle, via single-electron oxidative addition and photoreduction, has been proven by multiple in situ or operando techniques. This catalytic system demonstrates high efficiency and requires room temperature conditions and no additives, which improves the turnover frequency (TOF) to 1507 h-1. In particular, this unique mechanism has broken through the substrate limitation and shows a broad scope for different electronic effects of alkenes and alkynes.
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Affiliation(s)
- Guanglin Wang
- Center of Excellence for Environmental Safety and Biological Effects, Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry, College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China
- Beijing Key Laboratory of Microstructure and Property of Solids, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
| | - Yichang Liu
- Center of Excellence for Environmental Safety and Biological Effects, Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry, College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China
| | - Xiangyu Zhang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Xupeng Zong
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xu Zhang
- Beijing Key Laboratory of Microstructure and Property of Solids, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
| | - Kun Zheng
- Beijing Key Laboratory of Microstructure and Property of Solids, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
| | - Dan Qu
- Center of Excellence for Environmental Safety and Biological Effects, Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry, College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China
| | - Li An
- Center of Excellence for Environmental Safety and Biological Effects, Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry, College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China
| | - Xiaotian Qi
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Zaicheng Sun
- Center of Excellence for Environmental Safety and Biological Effects, Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry, College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China
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23
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Yu F, Wang W, Wang S. Copper-Catalyzed, Interrupted Remote Fluoromethylthiolation of Unactivated C(sp3)-H Bonds. Org Lett 2024; 26:2068-2072. [PMID: 38426710 DOI: 10.1021/acs.orglett.4c00336] [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
An efficient copper-catalyzed selective fluoromethylthiolation of an inert δ-C(sp3)-H bond in sulfonamides was reported. In the presence of a copper catalyst and PhSO2SRf, the radical generated through 1,5-hydrogen atom transfer (HAT) was sufficiently trapped by PhSO2SRf, instead of copper, which was prevalent in metal-catalyzed radical-relay processes, incorporating a fluoromethylthio group into molecules. The general substrate scope and mild conditions endowed the method with wide potential applications in pharmaceuticals and agrochemicals.
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Affiliation(s)
- Fan Yu
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China
| | - Wengui Wang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China
| | - Shoufeng Wang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China
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24
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He C, Wang Q, Zhou X, Yi L, Zhang Z, Zhang C, Xie H, Huang Q, Qiu G, Yang M. Photocatalytic Cyclization Cascades by Radical Relay toward Pyrrolo[1,2- a]indoles: Synthesis, Mechanism, and Application. J Org Chem 2024; 89:3509-3524. [PMID: 38362658 DOI: 10.1021/acs.joc.3c02959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
A photocatalytic annulation cascade of unactivated N-alkene-linked indoles with Langlois' reagent by a radical relay is developed at room temperature under blue LED irradiation. The reaction afforded a series of tri/difluoromethylated pyrrolo[1,2-a]indoles in moderate to good yields. The DFT study suggests that the reaction is ascribed to a rhodamine 6G-induced cyclization cascade involving vinyl addition-radical relay and hydrogen-atom-abstraction (HAA) processes, and interestingly, pyrrolo[1,2-a]indoles are applied as fluorescent dyes into the fluorescence spectrum and live-cell imaging. This paper represents an initial example on photocatalytic cyclization cascades by radical relay and the HAA process.
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Affiliation(s)
- Chen He
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
| | - Qi Wang
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
| | - Xiaoyang Zhou
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
| | - Lin Yi
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
| | - Zhiqiang Zhang
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
| | - Chun Zhang
- School of Pharmaceutical and Materials Engineering, Taizhou University, Taizhou, Zhejiang Province 318000, China
| | - Haijiao Xie
- Hangzhou Yanqu Information Technology Co., Ltd., Y2, second Floor, Building 2, Xixi Legu Creative Pioneering Park, No. 712 Wen'er West Road, Xihu District, Hangzhou City, Zhejiang Province 310003, China
| | - Qitong Huang
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
| | - Guanyinsheng Qiu
- College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001 Zhejiang, China
| | - Min Yang
- School of Pharmacy, Key Laboratory of Biomaterials and Biofabrication in Tissue Engineering of Jiangxi Province, Key Laboratory of Biomedical Sensors of Ganzhou, Gannan Medical University, Ganzhou, Jiangxi Province 341000, China
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25
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Ma Y. Computational Research on Ag(I)-Catalyzed Cubane Rearrangement: Mechanism, Metal and Counteranion Effect, Ligand Engineering, and Post-Transition-State Desymmetrization. J Org Chem 2024; 89:3430-3440. [PMID: 38375633 DOI: 10.1021/acs.joc.3c02891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Ag(I) salts have demonstrated superior catalytic activity in the cubane-cuneane rearrangement. This research presents a comprehensive mechanistic investigation using high-level computations. The reaction proceeds via oxidative addition (OA) of Ag(I) to the C-C bond, followed by C-Ag bond cleavage and subsequent dynamically concerted carbocation rearrangement. The OA of Ag(I) exhibits significant more electrophilic nature than classical transition metal-induced OA, and the superior catalytic activity of Ag(I) is attributed to the accessibility of a highly electrophilic "bare" Ag+ center and a relatively weak Ag-C bond. However, the highly Lewis acidic nature of the Ag(I) center limits the substrate scope. To address this problem, ligand and counteranion screening was conducted, revealing that chiral biarylether ligands in combination with BF4- as the counteranion offer both enhanced reactivity and improved chemoselectivity while suppressing the Lewis acidity. Additionally, quasi-classical molecular dynamics simulations indicate the possibility of a novel desymmetrization pathway through post-transition-state dynamics in the biarylether-Ag(I)-BF4- system, thereby providing a potential avenue for enantioselective cuneane synthesis.
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Affiliation(s)
- Yumiao Ma
- BSJ Institute, Haidian, Beijing 100084, People's Republic of China
- Hangzhou Yanqu Information Technology Co., Ltd., Xihu District, Hangzhou City, Zhejiang Province 310003, People's Republic of China
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26
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Zhu Y, Qiu YH, Dai XK, Luo W, Peng X, Chen Z, Yu D. Difluoromethylated Difunctionalization of Alkenes under Visible Light. J Org Chem 2024; 89:2525-2537. [PMID: 38300156 DOI: 10.1021/acs.joc.3c02552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Difluoromethylated compounds usually act as bioisosteres for alcohol functional groups and show unique physicochemical and biological properties. The cyano-difluoromethylation of alkenes using 5-((difluoromethyl)sulfonyl)-1-phenyl-1H-tetrazole as a CF2H radical difluoromethyl precursor was developed to afford nitriles including a CF2H group. A low-cost, stable, easily handled 5-((difluoromethyl)sulfonyl)-1-methyl-1H-tetrazole (DFSMT) was synthesized and applied as the radical CF2H reagent. Using DFSMT as the radical CF2H precursor, the oxyl-difluoromethylation of alkenes was developed to obtain difluoromethylated ether products. All of the reactions showed good functional group tolerability. Initial mechanistic experiments indicated that the CF2H radical was involved as the key active intermediate.
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Affiliation(s)
- Yuping Zhu
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, P. R. China
| | - Yan-Hua Qiu
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, P. R. China
| | - Xiao-Kang Dai
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, P. R. China
| | - Wenjun Luo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, P. R. China
| | - Xiangjun Peng
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, School of Pharmaceutical Sciences of Gannan Medical University, Ganzhou 341000, P. R. China
| | - Zhengwang Chen
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, P. R. China
| | - Daohong Yu
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, P. R. China
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27
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Wang M, Huang Y, Hu P. Terminal C(sp 3)-H borylation through intermolecular radical sampling. Science 2024; 383:537-544. [PMID: 38300993 DOI: 10.1126/science.adj9258] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024]
Abstract
Hydrogen atom transfer (HAT) processes can overcome the strong bond dissociation energies (BDEs) of inert C(sp3)-H bonds and thereby convert feedstock alkanes into value-added fine chemicals. Nevertheless, the high reactivity of HAT reagents, coupled with the small differences among various C(sp3)-H bond strengths, renders site-selective transformations of straight-chain alkanes a great challenge. Here, we present a photocatalytic intermolecular radical sampling process for the iron-catalyzed borylation of terminal C(sp3)-H bonds in substrates with small steric hindrance, including unbranched alkanes. Mechanistic investigations have revealed that the reaction proceeds through a reversible HAT process, followed by a selective borylation of carbon radicals. A boron-sulfoxide complex may contribute to the high terminal regioselectivity observed.
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Affiliation(s)
- Miao Wang
- Institute of Green Chemistry and Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Yahao Huang
- Institute of Green Chemistry and Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Peng Hu
- Institute of Green Chemistry and Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
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28
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Mandal M, Buss JA, Chen SJ, Cramer CJ, Stahl SS. Mechanistic insights into radical formation and functionalization in copper/ N-fluorobenzenesulfonimide radical-relay reactions. Chem Sci 2024; 15:1364-1373. [PMID: 38274066 PMCID: PMC10806759 DOI: 10.1039/d3sc03597b] [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: 07/13/2023] [Accepted: 12/09/2023] [Indexed: 01/27/2024] Open
Abstract
Copper-catalysed radical-relay reactions that employ N-fluorobenzenesulfonimide (NFSI) as the oxidant have emerged as highly effective methods for C(sp3)-H functionalization. Herein, computational studies are paired with experimental data to investigate a series of key mechanistic features of these reactions, with a focus on issues related to site-selectivity, enantioselectivity, and C-H substrate scope. (1) The full reaction energetics of enantioselective benzylic C-H cyanation are probed, and an adduct between Cu and the N-sulfonimidyl radical (˙NSI) is implicated as the species that promotes hydrogen-atom transfer (HAT) from the C-H substrate. (2) Benzylic versus 3° C-H site-selectivity is compared with different HAT reagents: Cu/˙NSI, ˙OtBu, and Cl˙, and the data provide insights into the high selectivity for benzylic C-H bonds in Cu/NFSI-catalyzed C-H functionalization reactions. (3) The energetics of three radical functionalization pathways are compared, including radical-polar crossover (RPC) to generate a carbocation intermediate, reductive elimination from a formal CuIII organometallic complex, and radical addition to a Cu-bound ligand. The preferred mechanism is shown to depend on the ligands bound to copper. (4) Finally, the energetics of three different pathways that convert benzylic C-H bonds into benzylic cations are compared, including HAT/ET (ET = electron transfer), relevant to the RPC mechanism with Cu/NFSI; hydride transfer, involved in reactions with high-potential quinones; and sequential ET/PT/ET (PT = proton transfer), involved in catalytic photoredox reactions. Collectively, the results provide mechanistic insights that establish a foundation for further advances in radical-relay C-H functionalization reactions.
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Affiliation(s)
- Mukunda Mandal
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota 207 Pleasant Street SE Minneapolis MN 55455 USA
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Joshua A Buss
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Si-Jie Chen
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Christopher J Cramer
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota 207 Pleasant Street SE Minneapolis MN 55455 USA
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
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29
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Wei Y, Wang Z, Wang K, Qiu JK, Wang Z, Li H, Duan X, Guo K, Bao X, Wu X. Copper-Catalyzed Radical Allene C(sp 2 )-H Cyanation. Angew Chem Int Ed Engl 2024; 63:e202317132. [PMID: 38038249 DOI: 10.1002/anie.202317132] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/02/2023]
Abstract
While the hydrogen atom abstraction (HAA) from C(sp3 )-H bond has been well explored, the radical-mediated chemo- and regio-selective functionalization of allenic C(sp2 )-H bond via direct HAA from C(sp2 )-H bond of allene remains an unsolved challenge in synthetic chemistry. This is primarily due to inherent challenges with addition of radical intermediates to allenes, regioselectivity of HAA process, instability of allenyl radical toward propargyl radical et al. Herein, we report a copper catalyzed allenic C(sp2 )-H cyanation of an array of tri- and di-substituted allenes with exceptional site-selectivity, while mono-substituted allene was successfully cyanated, albeit with a low yield. In the developed strategy, steric N-fluoro-N-alkylsulfonamide, serving as precursor of hydrogen atom abstractor, plays a crucial role in achieving the desired regioselectivity and avoiding addition of N-centered radical to allene.
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Affiliation(s)
- Youhao Wei
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
| | - Zheng Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
| | - Kaifeng Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
| | - Jiang-Kai Qiu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Zhaoshan Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
| | - Haotian Li
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
| | - Xiu Duan
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Kai Guo
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Xiaoguang Bao
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
| | - Xinxin Wu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu, 215123, China
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30
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Shi Y, Nie J, Wu Z, Ji X, Huang H. Photoredox Enabled Defluorinative Benzylation of Trifluoromethyl Alkenes with Alkylarenes. Org Lett 2024; 26:100-105. [PMID: 38147046 DOI: 10.1021/acs.orglett.3c03713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Herein, we report a photoredox enabled defluorinative benzylation of trifluoromethyl alkenes with readily available alkylarenes, which provides convenient access to a series of structurally valuable benzylated gem-difluoroalkenes under mild reaction conditions. The synthetic value of this protocol has been demonstrated by the transformations of several substrates bearing drug moieties, gram-scale reactions, and various further derivatizations of the gem-difluoroalkene products. The preliminary mechanistic investigations suggest a reaction pathway with rate-determining benzyl C-H bond cleavage of toluene followed by benzylic radical formation.
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Affiliation(s)
- Yutao Shi
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China
| | - Jinhuan Nie
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China
| | - Zhijie Wu
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China
| | - Xiaochen Ji
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, China
| | - Huawen Huang
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, China
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31
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Bo C, Li M, Chen F, Liu J, Dai B, Liu N. Visible-Light-Initiated Air-Oxygenation of Alkylarenes to Carbonyls Mediated by Carbon Tetrabromide in Water. CHEMSUSCHEM 2024; 17:e202301015. [PMID: 37661194 DOI: 10.1002/cssc.202301015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/25/2023] [Accepted: 09/01/2023] [Indexed: 09/05/2023]
Abstract
Synthesizing benzyl skeleton derivatives via direct oxidation of functionalized benzylic C-H bonds has received extensive research attention. Herein, a method was developed to prepare carbonyl compounds via photoinduced aerobic oxidation of ubiquitous benzylic C-H bonds mediated by bromine radicals and tribromomethane radicals. This method employed commercially available CBr4 as a hydrogen atom transfer reagent precursor, air as an oxidant, water as a reaction solvent, and tetrabutylammonium perchlorate (TBAPC) as an additive under mild conditions. A series of substrates bearing different functional groups was converted to aromatic carbonyls in moderate to good yields. Moreover, a low environmental factor (E-factor value=0.45) showed that the proposed method is ecofriendly and environmentally sustainable.
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Affiliation(s)
- Chunbo Bo
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Min Li
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Fei Chen
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Jichang Liu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Bin Dai
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Ning Liu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
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32
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Naeem Y, Matsuo BT, Davies HML. Enantioselective Intermolecular C-H Functionalization of Primary Benzylic C-H Bonds Using ((Aryl)(diazo)methyl)phosphonates. ACS Catal 2024; 14:124-130. [PMID: 38205024 PMCID: PMC10775147 DOI: 10.1021/acscatal.3c04661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 01/12/2024]
Abstract
Catalyst-controlled C-H functionalization using donor/acceptor carbenes has been shown to be an efficient process capable of high levels of site control and stereocontrol. This study demonstrated that the scope of the donor/acceptor carbene C-H functionalization can be extended to systems where the acceptor group is a phosphonate. When using the optimized dirhodium catalyst, Rh2(S-di-(4-Br)TPPTTL)4, ((aryl)(diazo)methyl)phosphonates undergo highly enantioselective (84-99% ee) and site-selective (>30:1 r.r.) benzylic C-H functionalization. The phosphonate group is much more sterically demanding than the previously studied carboxylate ester group, leading to much higher selectivity for a primary site versus more sterically crowded positions. The effectiveness of this methodology has been demonstrated by the late-stage primary C-H functionalization of estrone, adapalene, (S)-naproxen, clofibrate, and gemfibrozil derivatives.
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Affiliation(s)
- Yasir Naeem
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Bianca T. Matsuo
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Huw M. L. Davies
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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33
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Chen SJ, Krska SW, Stahl SS. Copper-Catalyzed Benzylic C-H Cross-Coupling Enabled by Redox Buffers: Expanding Synthetic Access to Three-Dimensional Chemical Space. Acc Chem Res 2023; 56:3604-3615. [PMID: 38051914 PMCID: PMC10902864 DOI: 10.1021/acs.accounts.3c00580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
ConspectusCross-coupling methods are the most widely used synthetic methods in medicinal chemistry. Existing reactions are dominated by methods such as amide coupling and arylation reactions that form bonds to sp2-hybridized carbon atoms and contribute to the formation of "flat" molecules. Evidence that three-dimensional structures often have improved physicochemical properties for pharmaceutical applications has contributed to growing demand for cross-coupling methods with sp3-hybridized reaction partners. Substituents attached to sp3 carbon atoms are intrinsically displayed in three dimensions. These considerations have led to efforts to establish reactions with sp3 cross-coupling partners, including alkyl halides, amines, alcohols, and carboxylic acids. As C(sp3)-H bonds are much more abundant that these more conventional coupling partners, we have been pursuing C(sp3)-H cross-coupling reactions that achieve site-selectivity, synthetic utility, and scope competitive with conventional coupling reactions.In this Account, we outline Cu-catalyzed oxidative cross-coupling reactions of benzylic C(sp3)-H bonds with diverse nucleophilic partners. These reactions commonly use N-fluorobenzenesulfonimide (NFSI) as the oxidant. The scope of reactivity is greatly improved by using a "redox buffer" that ensures that the Cu catalyst is available in the proper redox state to promote the reaction. Early precedents of catalytic Cu/NFSI oxidative coupling reactions, including C-H cyanation and arylation, did not require a redox buffer, but reactions with other nucleophiles, such as alcohols and azoles, were much less effective under similar conditions. Mechanistic studies show that some nucleophiles, such as cyanide and arylboronic acids, promote in situ reduction of CuII to CuI, contributing to successful catalytic turnover. Poor reactivity was observed with nucleophiles, such as alcohols, that do not promote CuII reduction in the same manner. This insight led to the identification of sacrificial reductants, termed "redox buffers", that support controlled generation of CuI during the reactions and enable successful benzylic C(sp3)-H cross-coupling with diverse nucleophiles. Successful reactions include those that feature direct coupling of (hetero)benzylic C-H substrates with coupling partners (alcohols, azoles) and sequential C(sp3)-H functionalization/coupling reactions. The latter methods feature generation of a synthetic linchpin that can undergo subsequent reaction with a broad array of nucleophiles. For example, halogenation/substitution cascades afford benzylic amines, (thio)ethers, and heterodiarylmethane derivatives, and an isocyanation/amine-addition sequence generates diverse benzylic ureas.Collectively, these Cu-catalyzed (hetero)benzylic C(sp3)-H cross-coupling reactions rapidly access diverse molecules. Analysis of their physicochemical and topological properties highlights the "drug-likeness" and enhanced three-dimensionality of these products relative to existing bioactive molecules. This consideration, together with the high benzylic C-H site-selectivity and the broad scope of reactivity enabled by the redox buffering strategy, makes these C(sp3)-H cross-coupling methods ideally suited for implementation in high-throughput experimentation platforms to explore novel chemical space for drug discovery and related applications.
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Affiliation(s)
- Si-Jie Chen
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
- Department of Discovery Chemistry, Merck & Co., Inc., 213 E Grand Avenue, South San Francisco, California, 94030, United States
| | - Shane W. Krska
- Department of Discovery Chemistry, Merck & Co., Inc., 126 East Lincoln Ave., Rahway, New Jersey 07065, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
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34
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Huang J, Gao Q, Zhong T, Chen S, Lin W, Han J, Xie J. Photoinduced copper-catalyzed C-N coupling with trifluoromethylated arenes. Nat Commun 2023; 14:8292. [PMID: 38092783 PMCID: PMC10719352 DOI: 10.1038/s41467-023-44097-y] [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: 08/29/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Selective defluorinative functionalization of trifluoromethyl group (-CF3) is an attractive synthetic route to the pharmaceutically privileged fluorine-containing moiety. Herein, we report a strategy based on photoexcited copper catalysis to activate the C-F bond of di- or trifluoromethylated arenes for divergent radical C-N coupling with carbazoles and aromatic amines. The use of different ligands can tune the reaction products diversity. A range of substituted, structurally diverse α,α-difluoromethylamines can be obtained from trifluoromethylated arenes via defluorinative C-N coupling with carbazoles, while an interesting double defluorinative C-N coupling is ready for difluoromethylated arenes. Based on this success, a carbazole-centered PNP ligand is designed to be an optimal ligand, enabling a copper-catalyzed C-N coupling for the construction of imidoyl fluorides from aromatic amines through double C-F bond functionalization. Interestingly, a 1,2-difluoroalkylamination strategy of styrenes is also developed, delivering γ,γ-difluoroalkylamines, a bioisostere to β-aminoketones, in synthetically useful yields. The DFT studies reveal an inner-sphere electron transfer mechanism for Cu-catalyzed selective activation of C(sp3)-F bonds.
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Affiliation(s)
- Jun Huang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Qi Gao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Tao Zhong
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Shuai Chen
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Wei Lin
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou, 213001, China
| | - Jie Han
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Jin Xie
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
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35
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Cheng Z, Yang T, Li C, Deng Y, Zhang F, Chen P, Lin Z, Ma S, Liu G. Site-Selective sp 2 C-H Cyanation of Allenes via Copper-Catalyzed Radical Relay. J Am Chem Soc 2023; 145:25995-26002. [PMID: 38011726 DOI: 10.1021/jacs.3c11368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Compared with the extensively reported hydrogen atom transfer (HAT) at sp3 C-H, abstraction of hydrogen atoms at the sp2 carbon is extremely rare. Here, we communicate the site-selective cyanation of the sp2 C-H bond of allenes using the strategy of copper-catalyzed radical relay. The reactions afford various allenyl nitriles directly from simple allenes with a broad substrate scope and a remarkable functional group compatibility under mild conditions. These reactions exhibit excellent site-selectivity toward sp2 C-H, which can be attributed to the unique pocket created by the Cu-bound nitrogen-centered radical. The favorable HAT on sp2 C-H is due to crucial hydrogen bonding between the fluoride bonded to the Cu(II) center and the hydrogen atom at the allylic position. These features enable the late-stage functionalization of druglike bioactive molecules containing an allene motif.
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Affiliation(s)
- Zhongming Cheng
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Tilong Yang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Can Li
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yunshun Deng
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Fangjia Zhang
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Pinhong Chen
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Shengming Ma
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Guosheng Liu
- State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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36
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Li HH, Chen X, Kramer S. Recent developments for intermolecular enantioselective amination of non-acidic C(sp 3)-H bonds. Chem Sci 2023; 14:13278-13289. [PMID: 38033905 PMCID: PMC10686044 DOI: 10.1039/d3sc04643e] [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: 09/04/2023] [Accepted: 11/07/2023] [Indexed: 12/02/2023] Open
Abstract
Enantioenriched chiral amines are of exceptional importance in the pharmaceutical industry. Recently, several new methods for the installation of these functional groups directly from non-acidic C(sp3)-H bonds by catalytic intermolecular enantioselective amination have been reported. These methods represent significant advances of the field and most of them display high levels of enantioselectivity, utilize the C(sp3)-H substrate as the limiting reagent, feature good functional group tolerance, and show compatibility with late-stage C(sp3)-H amination of advanced substrates. This perspective provides an overview of the recent developments in this rapidly advancing field and outlines possibilities and limitations, which will help identify unsolved challenges and guide future research efforts.
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Affiliation(s)
- Heng-Hui Li
- Department of Chemistry, Technical University of Denmark 2800 Kgs. Lyngby Denmark
| | - Xuemeng Chen
- Department of Chemistry, Technical University of Denmark 2800 Kgs. Lyngby Denmark
| | - Søren Kramer
- Department of Chemistry, Technical University of Denmark 2800 Kgs. Lyngby Denmark
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37
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Chen A, Qiao Y, Gao DW. Controllable Regiodivergent Alkynylation of 1,3-Bis(Boronic) Esters Activated by Distinct Organometallic Reagents. Angew Chem Int Ed Engl 2023; 62:e202312605. [PMID: 37849448 DOI: 10.1002/anie.202312605] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/19/2023]
Abstract
1,3-Bis(boronic) esters can be readily synthesized from alkylBpin precursors. Selective transformations of these compounds hold the potential for late-stage functionalization of the remaining C-B bond, leading to a diverse array of molecules. Currently, there are no strategies available to address the reactivity and, more importantly, the controllable regiodivergent functionalization of 1,3-bis(boronic) esters. In this study, we have achieved controllable regiodivergent alkynylation of these molecules. The regioselectivity has been clarified based on the unique chelation patterns observed with different organometallic reagents. Remarkably, this methodology effectively addresses the low reactivity of 1,3-bis(boronic) esters and bridges the gap in radical chemistry, which typically yields only the classical products formed via stable radical intermediates. Furthermore, the compounds synthesized through this approach serve as potent building blocks for creating molecular diversity.
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Affiliation(s)
- Ang Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Yang Qiao
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - De-Wei Gao
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
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38
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Wu Y, Zhang W, Ma S, Song C, Chang J. Copper-Catalyzed Synthesis of N-Fused Quinolines via C(sp 3)-H Activation-Radical Addition-Cyclization Cascade. J Org Chem 2023. [PMID: 38012068 DOI: 10.1021/acs.joc.3c01812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
A novel copper-catalyzed cyclization reaction for the synthesis of pyrazolo[1,5-a]quinoline, triazolo[1,5-a]quinoline, and pyrrolo[1,2-a]quinoline derivatives is described. The process is initiated by di-tert-butyl peroxide-mediated C(sp3)-H activation to generate the α-functionalized radical, which supervenes a cascade radical addition/cyclization sequence to access the N-fused quinolines in good yields with broad functional group tolerance.
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Affiliation(s)
- Yangang Wu
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Wen Zhang
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Shiyu Ma
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Chuanjun Song
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Junbiao Chang
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
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39
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Su F, Lu F, Tang K, Lv X, Luo Z, Che F, Long H, Wu X, Chi YR. Organocatalytic C-H Functionalization of Simple Alkanes. Angew Chem Int Ed Engl 2023; 62:e202310072. [PMID: 37731165 DOI: 10.1002/anie.202310072] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/22/2023]
Abstract
The direct functionalization of inert C(sp3 )-H bonds to form carbon-carbon and carbon-heteroatom bonds offers vast potential for chemical synthesis and therefore receives increasing attention. At present, most successes come from strategies using metal catalysts/reagents or photo/electrochemical processes. The use of organocatalysis for this purpose remains scarce, especially when dealing with challenging C-H bonds such as those from simple alkanes. Here we disclose the first organocatalytic direct functionalization/acylation of inert C(sp3 )-H bonds of completely unfunctionalized alkanes. Our approach involves N-heterocyclic carbene catalyst-mediated carbonyl radical intermediate generation and coupling with simple alkanes (through the corresponding alkyl radical intermediates generated via a hydrogen atom transfer process). Unreactive C-H bonds are widely present in fossil fuel feedstocks, commercially important organic polymers, and complex molecules such as natural products. Our present study shall inspire a new avenue for quick functionalization of these molecules under the light- and metal-free catalytic conditions.
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Affiliation(s)
- Fen Su
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Fengfei Lu
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Kun Tang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Xiaokang Lv
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Zhongfu Luo
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Fengrui Che
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Hongyan Long
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Xingxing Wu
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Yonggui Robin Chi
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
- School of chemistry, chemical engineering, and biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
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40
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Qian PF, Zhou T, Shi BF. Transition-metal-catalyzed atroposelective synthesis of axially chiral styrenes. Chem Commun (Camb) 2023; 59:12669-12684. [PMID: 37807950 DOI: 10.1039/d3cc03592a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Axially chiral styrenes, a type of atropisomer analogous to biaryls, have attracted great interest because of their unique presence in natural products and asymmetric catalysis. Since 2016, a number of methodologies have been developed for the atroposelective construction of these chiral skeletons, involving both transition metal catalysis and organocatalysis. In this feature article, we aim to provide a comprehensive understanding of recent advances in the asymmetric synthesis of axially chiral styrenes catalyzed by transition metals, integrating scattered work with different catalytic systems together. This feature article is cataloged into five sections according to the strategies, including asymmetric coupling, enantioselective C-H activation, central-to-axial chirality transfer, asymmetric alkyne functionalization, and atroposelective [2+2+2] cycloaddition.
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Affiliation(s)
- Pu-Fan Qian
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
| | - Tao Zhou
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
| | - Bing-Feng Shi
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
- College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
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41
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Wang Y, Dana S, Long H, Xu Y, Li Y, Kaplaneris N, Ackermann L. Electrochemical Late-Stage Functionalization. Chem Rev 2023; 123:11269-11335. [PMID: 37751573 PMCID: PMC10571048 DOI: 10.1021/acs.chemrev.3c00158] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Indexed: 09/28/2023]
Abstract
Late-stage functionalization (LSF) constitutes a powerful strategy for the assembly or diversification of novel molecular entities with improved physicochemical or biological activities. LSF can thus greatly accelerate the development of medicinally relevant compounds, crop protecting agents, and functional materials. Electrochemical molecular synthesis has emerged as an environmentally friendly platform for the transformation of organic compounds. Over the past decade, electrochemical late-stage functionalization (eLSF) has gained major momentum, which is summarized herein up to February 2023.
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Affiliation(s)
| | | | | | - Yang Xu
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Yanjun Li
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Nikolaos Kaplaneris
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Lutz Ackermann
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
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42
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Chen SJ, He CQ, Kong M, Wang J, Lin S, Krska SW, Stahl SS. Accessing three-dimensional molecular diversity through benzylic C-H cross-coupling. NATURE SYNTHESIS 2023; 2:998-1008. [PMID: 38463240 PMCID: PMC10923599 DOI: 10.1038/s44160-023-00332-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 04/25/2023] [Indexed: 03/12/2024]
Abstract
Pharmaceutical and agrochemical discovery efforts rely on robust methods for chemical synthesis that rapidly access diverse molecules1,2. Cross-coupling reactions are the most widely used synthetic methods3, but these methods typically form bonds to C(sp2)-hybridized carbon atoms (e.g., amide coupling, biaryl coupling) and lead to a prevalence of "flat" molecular structures with suboptimal physicochemical and topological properties4. Benzylic C(sp3)-H cross-coupling methods offer an appealing strategy to address this limitation by directly forming bonds to C(sp3)-hybridized carbon atoms, and emerging methods exhibit synthetic versatility that rivals conventional cross-coupling methods to access products with drug-like properties. Here, we use a virtual library of >350,000 benzylic ethers and ureas derived from benzylic C-H cross-coupling to test the widely held view that coupling at C(sp3)-hybridized carbon atoms affords products with improved three-dimensionality. The results show that the conformational rigidity of the benzylic scaffold strongly influences the product dimensionality. Products derived from flexible scaffolds often exhibit little or no improvement in three-dimensionality, unless they adopt higher energy conformations. This outcome introduces an important consideration when designing routes to topologically diverse molecular libraries. The concepts elaborated herein are validated experimentally through an informatics-guided synthesis of selected targets and the use of high-throughput experimentation to prepare a library of three-dimensional products that are broadly distributed across drug-like chemical space.
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Affiliation(s)
- Si-Jie Chen
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI, USA
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, CA, USA
| | - Cyndi Qixin He
- Department of Discovery Chemistry, Merck & Co., Inc., Kenilworth, NJ, USA
| | - May Kong
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, CA, USA
| | - Jun Wang
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, CA, USA
| | - Shishi Lin
- Department of Discovery Chemistry, Merck & Co., Inc., Kenilworth, NJ, USA
| | - Shane W. Krska
- Department of Discovery Chemistry, Merck & Co., Inc., Kenilworth, NJ, USA
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI, USA
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43
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Hashimoto K, Higuchi D, Matsubara S, Murakami K. Copper-catalyzed reaction of aziridine for the synthesis of substituted imidazolidine and imidazolidinone. Front Chem 2023; 11:1272034. [PMID: 37841205 PMCID: PMC10570437 DOI: 10.3389/fchem.2023.1272034] [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: 08/03/2023] [Accepted: 09/18/2023] [Indexed: 10/17/2023] Open
Abstract
Herein we report a copper-catalyzed synthesis of imidazolidine by employing the reaction of aziridine with imine. The reaction smoothly provided a diverse range of 2-substituted imidazolidines with high compatibility with various functional groups. Moreover, during our investigation, we discovered that isocyanate also reacted with aziridine to yield substituted imidazolidinones efficiently. The versatility of these reactions was further demonstrated by their application in the synthesis of hybrid molecules derived from two pharmaceutical compounds. This approach opens new possibilities for the discovery of novel classes of bioactive molecules.
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Affiliation(s)
- Kota Hashimoto
- Department of Chemistry, School of Science, Kwansei Gakuin University, Sanda, Japan
| | - Daiki Higuchi
- Department of Chemistry, School of Science, Kwansei Gakuin University, Sanda, Japan
| | - Satoshi Matsubara
- Department of Chemistry, School of Science, Kwansei Gakuin University, Sanda, Japan
| | - Kei Murakami
- Department of Chemistry, School of Science, Kwansei Gakuin University, Sanda, Japan
- JST-PRESTO, Chiyoda, Japan
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44
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Wu J, Shu C, Li Z, Noble A, Aggarwal VK. Photoredox-Catalyzed Decarboxylative Bromination, Chlorination and Thiocyanation Using Inorganic Salts. Angew Chem Int Ed Engl 2023; 62:e202309684. [PMID: 37522816 PMCID: PMC10952529 DOI: 10.1002/anie.202309684] [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: 07/07/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/01/2023]
Abstract
Decarboxylative halogenation reactions of alkyl carboxylic acids are highly valuable reactions for the synthesis of structurally diverse alkyl halides. However, many reported protocols rely on stoichiometric strong oxidants or highly electrophilic halogenating agents. Herein, we describe visible-light photoredox-catalyzed decarboxylative halogenation reactions of N-hydroxyphthalimide-activated carboxylic acids that avoid stoichiometric oxidants and use inexpensive inorganic halide salts as the halogenating agents. Bromination with lithium bromide proceeds under simple, transition-metal-free conditions using an organic photoredox catalyst and no other additives, whereas dual photoredox-copper catalysis is required for chlorination with lithium chloride. The mild conditions display excellent functional-group tolerance, which is demonstrated through the transformation of a diverse range of structurally complex carboxylic acid containing natural products into the corresponding alkyl bromides and chlorides. In addition, we show the generality of the dual photoredox-copper-catalyzed decarboxylative functionalization with inorganic salts by extension to thiocyanation with potassium thiocyanide, which was applied to the synthesis of complex alkyl thiocyanates.
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Affiliation(s)
- Jingjing Wu
- School of ChemistryUniversity of BristolCantock's CloseBS8 1TSBristolUK
- Current address: Frontiers Science Center for Transformative MoleculesSchool of Chemistry and Chemical EngineeringZhangjiang Institute for Advanced StudyShanghai Jiao Tong UniversityNo. 429, Zhangheng Road200213ShanghaiChina
| | - Chao Shu
- School of ChemistryUniversity of BristolCantock's CloseBS8 1TSBristolUK
- Current address: National Key Laboratory of Green PesticideCollege of ChemistryCentral China Normal University (CCNU)152 Luoyu Road430079WuhanHubeiChina
| | - Zhihang Li
- School of ChemistryUniversity of BristolCantock's CloseBS8 1TSBristolUK
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBS8 1TSBristolUK
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45
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Borrel J, Waser J. Azido-alkynylation of alkenes through radical-polar crossover. Chem Sci 2023; 14:9452-9460. [PMID: 37712015 PMCID: PMC10498506 DOI: 10.1039/d3sc03309k] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/10/2023] [Indexed: 09/16/2023] Open
Abstract
We report an azido-alkynylation of alkenes allowing a straightforward access to homopropargylic azides by combining hypervalent iodine reagents and alkynyl-trifluoroborate salts. The design of a photocatalytic redox-neutral radical polar crossover process was key to develop this transformation. A variety of homopropargylic azides possessing electron-rich and -poor aryls, heterocycles or ether substituents could be accessed in 34-84% yield. The products are synthetically useful building blocks that could be easily transformed into pyrroles or bioactive amines.
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Affiliation(s)
- Julien Borrel
- Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
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46
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Maity S, Lopez MA, Bates DM, Lin S, Krska SW, Stahl SS. Polar Heterobenzylic C(sp 3)-H Chlorination Pathway Enabling Efficient Diversification of Aromatic Nitrogen Heterocycles. J Am Chem Soc 2023; 145:19832-19839. [PMID: 37642292 PMCID: PMC10629438 DOI: 10.1021/jacs.3c05822] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Site-selective radical reactions of benzylic C-H bonds are now highly effective methods for C(sp3-H) functionalization and cross-coupling. The existing methods, however, are often ineffective with heterobenzylic C-H bonds in alkyl-substituted pyridines and related aromatic heterocycles that are prominently featured in pharmaceuticals and agrochemicals. Here, we report new synthetic methods that leverage polar, rather than radical, reaction pathways to enable the selective heterobenzylic C-H chlorination of 2- and 4-alkyl-substituted pyridines and other heterocycles. Catalytic activation of the substrate with trifluoromethanesulfonyl chloride promotes the formation of enamine tautomers that react readily with electrophilic chlorination reagents. The resulting heterobenzyl chlorides can be used without isolation or purification in nucleophilic coupling reactions. This chlorination-diversification sequence provides an efficient strategy to achieve heterobenzylic C-H cross-coupling with aliphatic amines and a diverse collection of azoles, among other coupling partners.
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Affiliation(s)
- Soham Maity
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Marco A. Lopez
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Desiree M. Bates
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Shishi Lin
- Discovery Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ 07033, United States
| | - Shane W. Krska
- Discovery Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ 07033, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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47
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Guan J, Chen J, Luo Y, Guo L, Zhang W. Copper-Catalyzed Chemoselective Asymmetric Hydrogenation of C=O Bonds of Exocyclic α,β-Unsaturated Pentanones. Angew Chem Int Ed Engl 2023; 62:e202306380. [PMID: 37307027 DOI: 10.1002/anie.202306380] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 06/13/2023]
Abstract
A highly chemoselective earth-abundant transition metal copper catalyzed asymmetric hydrogenation of C=O bonds of exocyclic α,β-unsaturated pentanones was realized using H2 . The desired products were obtained with up to 99 % yield and 96 % ee (enantiomeric excess) (99 % ee, after recrystallization). The corresponding chiral exocyclic allylic pentanol products can be converted into several bioactive molecules. The hydrogenation mechanism was investigated via deuterium-labelling experiments and control experiments, which indicate that the keto-enol isomerization rate of the substrate is faster than that of the hydrogenation and also show that the Cu-H complex can only catalyze chemoselectively the asymmetric reduction of the carbonyl group. Computational results indicate that the multiple attractive dispersion interactions (MADI effect) between the catalyst with bulky substituents and substrate play important roles which stabilize the transition states and reduce the generation of by-products.
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Affiliation(s)
- Jing Guan
- Frontier Science Center for Transformative Molecules, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Jianzhong Chen
- Frontier Science Center for Transformative Molecules, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Yicong Luo
- Frontier Science Center for Transformative Molecules, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Lisen Guo
- Frontier Science Center for Transformative Molecules, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Wanbin Zhang
- Frontier Science Center for Transformative Molecules, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University 800 Dongchuan Road, Shanghai, 200240, P. R. China
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48
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Liu Y, Yan H, Chen Y, Hao E, Shi L. Photoinduced copper-catalyzed selective three-component 1,2-amino oxygenation of 1,3-dienes. Chem Commun (Camb) 2023; 59:10388-10391. [PMID: 37551551 DOI: 10.1039/d3cc02769d] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
This study presents a highly effective method for the photoinduced copper-catalyzed 1,2-amino oxygenation of 1,3-dienes. This synthetic strategy involves the dual roles of a single copper catalyst, which can act as a photosensitizer to generate nitrogen radicals and can also react with allyl radicals via single electron transfer (SET) processes. The method produces a range of quaternary carbon-centered allyl carboxylic esters and tertiary ethers with high yields and excellent regioselectivity under mild reaction conditions.
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Affiliation(s)
- Yonghong Liu
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China.
| | - Huaipu Yan
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China.
| | - Yuqing Chen
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China.
| | - Erjun Hao
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, 453007, Xinxiang, China
| | - Lei Shi
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China.
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, 453007, Xinxiang, China
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49
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Ruos ME, Kinney RG, Ring OT, Doyle AG. A General Photocatalytic Strategy for Nucleophilic Amination of Primary and Secondary Benzylic C-H Bonds. J Am Chem Soc 2023; 145:18487-18496. [PMID: 37565772 DOI: 10.1021/jacs.3c04912] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
We report a visible-light photoredox-catalyzed method that enables nucleophilic amination of primary and secondary benzylic C(sp3)-H bonds. A novel amidyl radical precursor and organic photocatalyst operate in tandem to transform primary and secondary benzylic C(sp3)-H bonds into carbocations via sequential hydrogen atom transfer (HAT) and oxidative radical-polar crossover. The resulting carbocation can be intercepted by a variety of N-centered nucleophiles, including nitriles (Ritter reaction), amides, carbamates, sulfonamides, and azoles, for the construction of pharmaceutically relevant C(sp3)-N bonds under unified reaction conditions. Mechanistic studies indicate that HAT is amidyl radical-mediated and that the photocatalyst operates via a reductive quenching pathway. These findings establish a mild, metal-free, and modular protocol for the rapid diversification of C(sp3)-H bonds to a library of aminated products.
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Affiliation(s)
- Madeline E Ruos
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - R Garrison Kinney
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Oliver T Ring
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
- Early Chemical Development, Pharmaceutical Sciences, Biopharmaceuticals R&D, AstraZeneca, Gothenburg, SE-431 83 Mölndal, Sweden
| | - Abigail G Doyle
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
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Wang C, Qi R, Wang R, Xu Z. Photoinduced C(sp 3)-H Functionalization of Glycine Derivatives: Preparation of Unnatural α-Amino Acids and Late-Stage Modification of Peptides. Acc Chem Res 2023. [PMID: 37467427 DOI: 10.1021/acs.accounts.3c00260] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
ConspectusPeptides are essential components of living systems and contribute to critical biological processes, such as cell proliferation, immune defense, tumor formation, and differentiation. Therefore, peptides have attracted considerable attention as targets for the development of therapeutic products. The incorporation of unnatural amino acid residues into peptides can considerably impact peptide immunogenicity, toxicity, side effects, water solubility, action duration, and distribution and enhance the peptides' druggability. Typically, the direct modification of natural amino acids is a practical and effective approach for promptly obtaining unnatural amino acids. However, selective functionalization of multiple C(sp3)-H bonds with comparable chemical reactivities in the peptide side chains remains a formidable challenge. Furthermore, chemical modifications aimed at highly reactive (nucleophilic and aromatic) groups on peptide side chains can interfere with the biological activity of peptides.In recent years, the rapid advancement of photoinduced radical reactions has made photoredox radical-radical cross-coupling a practical approach for constructing C(sp3)-C(sp3) bonds under mild conditions. Glycine, a naturally occurring amino acid and the fundamental skeleton of all α-amino acids, provides a basis for the alkylated modification of its own α-C(sp3)-H bond under mild conditions. This Account describes our recent research endeavors for systematically investigating the photocatalytic α-C(sp3)-H alkylation of glycine derivatives via radical-radical coupling between N-aryl glycinate-derived radicals and various alkyl radicals. In 2018, we disclosed the photoinduced Cu-catalyzed decarboxylative α-C(sp3)-H alkylation of glycine derivatives. Subsequently, we developed a catalyst-free method for alkylating glycine derivatives and glycine residues in peptides via electron donor-acceptor (EDA)-complex-promoted single electron transfer. Moreover, we developed a photoinduced method for the radical alkylation of N-aryl glycinate α-C(sp3)-H bonds using unactivated alkyl chlorides (iodides) under photocatalyst-free conditions. Notably, by building on racemic alkylations of glycine derivatives and glycine-residue-containing peptides, we recently stereoselectively alkylated the N-aryl glycinate α-C(sp3)-H bond using a dual-functional Cu catalyst generated in situ for synthesizing a series of unnatural chiral α-amino and C-glycoamino acids.We have developed a series of methods for synthesizing unnatural amino acids through the α-C(sp3)-H alkylation of glycine derivatives using photoredox-promoted radical coupling as a key strategy. These methods are efficient and versatile and can be used for the late-stage modification of peptides in various contexts. Our work builds on the fundamental importance of glycine as the basic scaffold of all α-amino acids and highlights the potential of radical-based chemistry for developing chemical transformations in peptide synthesis. These findings have broad implications for chemical biology and may open doors for discovering peptide drugs and developing therapeutics.
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Affiliation(s)
- Chao Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Science, Lanzhou University, 199 West Donggang Road, Lanzhou 730000, China
| | - Rupeng Qi
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Science, Lanzhou University, 199 West Donggang Road, Lanzhou 730000, China
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Science, Lanzhou University, 199 West Donggang Road, Lanzhou 730000, China
- Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 199 West Donggang Road, Lanzhou 730000, China
| | - Zhaoqing Xu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Science, Lanzhou University, 199 West Donggang Road, Lanzhou 730000, China
- Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 199 West Donggang Road, Lanzhou 730000, China
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