1
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Fang CZ, Zhang BB, Tu YL, Liu Q, Wang ZX, Chen XY. Radical Replacement Process for Ligated Boryl Radical-Mediated Activation of Unactivated Alkyl Chlorides for C(sp 3)-C(sp 3) Bond Formation. J Am Chem Soc 2024; 146:26574-26584. [PMID: 39264946 DOI: 10.1021/jacs.4c10915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024]
Abstract
The ligated boryl radical (LBR) has emerged as a potent tool for activating alkyl halides in radical transformations through halogen-atom transfer (XAT). However, unactivated alkyl chlorides still present an open challenge for this strategy. We herein describe a new activation mode of the LBR for the activation of unactivated alkyl chlorides to construct a C(sp3)-C(sp3) bond. Mechanistic studies reveal that the success of the protocol relies on a radical replacement process between the LBR and unactivated alkyl chloride, forming an alkyl borane intermediate as the alkyl radical precursor. Aided with the additive K3PO4, the alkyl borane then undergoes one-electron oxidation, generating an alkyl radical. The incorporation of the radical replacement activation model to activate unactivated alkyl chlorides significantly enriches LBR chemistry, which has been applied to activate alkyl iodides, alkyl bromides, and activated alkyl chlorides via XAT.
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Affiliation(s)
- Chang-Zhen Fang
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100049, China
| | - Bei-Bei Zhang
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100049, China
| | - Yong-Liang Tu
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100049, China
| | - Qiang Liu
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100049, China
| | - Zhi-Xiang Wang
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100049, China
- Binzhou Institute of Technology, Weiqiao-UCAS Science and Technology Park, Binzhou, Shandong Province 256606, China
| | - Xiang-Yu Chen
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100049, China
- Binzhou Institute of Technology, Weiqiao-UCAS Science and Technology Park, Binzhou, Shandong Province 256606, China
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2
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Buettner C, Stavagna C, Tilby MJ, Górski B, Douglas JJ, Yasukawa N, Leonori D. Synthesis and Suzuki-Miyaura Cross-Coupling of Alkyl Amine-Boranes. A Boryl Radical-Enabled Strategy. J Am Chem Soc 2024; 146:24042-24052. [PMID: 39137918 PMCID: PMC11363021 DOI: 10.1021/jacs.4c07767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2024] [Revised: 07/17/2024] [Accepted: 07/18/2024] [Indexed: 08/15/2024]
Abstract
Alkyl organoborons are powerful materials for the construction of C(sp3)-C(sp2) bonds, predominantly via Suzuki-Miyaura cross-coupling. These species are generally assembled using 2-electron processes that harness the ability of boron reagents to act as both electrophiles and nucleophiles. Herein, we demonstrate an alternative borylation strategy based on the reactivity of amine-ligated boryl radicals. This process features the use of a carboxylic acid containing amine-ligated borane that acts as boryl radical precursor for photoredox oxidation and decarboxylation. The resulting amine-ligated boryl radical undergoes facile addition to styrenes and imines through radical-polar crossover manifolds. This delivers a new class of sp3-organoborons that are stable solids and do not undergo protodeboronation. These novel materials include unprotected α-amino derivatives that are generally unstable. Crucially, these aliphatic organoboron species can be directly engaged in Suzuki-Miyaura cross-couplings with structurally complex aryl halides. Preliminary studies suggest that they enable slow-release of the corresponding and often difficult to handle alkyl boronic acids.
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Affiliation(s)
- Cornelia
S. Buettner
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Chiara Stavagna
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Michael J. Tilby
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - Bartosz Górski
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - James J. Douglas
- Early
Chemical Development, Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Naoki Yasukawa
- Department
of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Daniele Leonori
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
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3
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Koo J, Kim W, Jhun BH, Park S, Song D, You Y, Lee HG. Halogen Atom Transfer-Induced Homolysis of C-F Bonds by the Excited-State Boryl Radical. J Am Chem Soc 2024; 146:22874-22880. [PMID: 39093360 DOI: 10.1021/jacs.4c06337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
A novel reactivity toward C-F bond functionalization has been developed, which could be designated as fluorine atom transfer (FAT). A photoexcited state of an N-heterocyclic carbene-ligated boryl radical exhibits a transcendent reactivity, capable of activating chemically inert carbon-fluorine bonds through homolysis. Combined experimental and computational studies suggest that the ligated boryl radical species directly abstracts a fluorine atom from the organofluoride substrates to provide valuable carbon-centered radicals.
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Affiliation(s)
- Jangwoo Koo
- Department of Chemistry, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Weonjeong Kim
- Department of Chemistry, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Byung Hak Jhun
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Subin Park
- Department of Chemistry, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Dayoon Song
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Youngmin You
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Hong Geun Lee
- Department of Chemistry, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
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4
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Li Y, Zhou Y, Zhou D, Jiang Y, Butt M, Yang H, Que Y, Li Z, Chen G. Regioselective Homolytic C 2-H Borylation of Unprotected Adenosine and Adenine Derivatives via Minisci Reaction. J Am Chem Soc 2024; 146:21428-21441. [PMID: 39051926 DOI: 10.1021/jacs.4c03865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
A Minisci-type borylation of unprotected adenosine, adenine nucleotide, and adenosine analogues was successfully achieved through photocatalysis or thermal activation. Despite the challenges posed by the presence of two potential reactive sites (C2 and C8) in the purine motif, the unique nucleophilic amine-ligated boryl radicals effortlessly achieved excellent C2 site selectivity and simultaneously avoided the formation of multifunctionalized products. This protocol proved effective for the late-stage borylation of some important biomolecules as well as a few antiviral and antitumor drug molecules, such as AMP, cAMP, Vidarabine, Cordycepin, Tenofovir, Adefovir, GS-441524, etc. Theoretical calculations shed light on the site selectivity, revealing that the free energy barriers for the C2-Minisci addition are further lowered through the chelation of additive Mg2+ to N3 and furyl oxygen. This phenomenon has been confirmed by an IGMH analysis. Preliminary antitumor evaluation, derivation of the C2-borylated adenosine to other analogues with high-value functionalities, along with the CuAAC click reactions, suggest the potential application of this methodology in drug molecular optimization studies and chemical biology.
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Affiliation(s)
- Yangyan Li
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Yutong Zhou
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
- Key Laboratory of Green and High-value Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai, P. R. China
| | - Dazhi Zhou
- Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
| | - Yujie Jiang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Madiha Butt
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Hui Yang
- Key Laboratory of Biocatalysis and Chiral Drug Synthesis of Guizhou Province, Generic Drug Research Center of Guizhou Province, Department of Pharmacy, Zunyi Medical University, Zunyi 563000, P. R. China
| | - Yingchuan Que
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Zhiming Li
- Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
| | - Gang Chen
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
- Key Laboratory of Green and High-value Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai, P. R. China
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5
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Phang YL, Jin JK, Zhang FL, Wang YF. Radical hydroboration for the synthesis of organoboron compounds. Chem Commun (Camb) 2024; 60:4275-4289. [PMID: 38566567 DOI: 10.1039/d4cc00398e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Organoboron compounds demonstrate diverse applications in the fields of organic synthesis, materials science, and medicinal chemistry. Compared to the conventional hydroboration reaction, radical hydroboration serves as an alternative approach for the synthesis of organoborons via different mechanisms. In radical hydroboration, a boryl radical is initially generated from homolytic cleavage of a B-H or a B-B bond, which is then added to an unsaturated double bond to deliver a carbon radical. Subsequent hydrogen atom transfer or reduction of the carbon radical to form a carbanion followed by protonation gave the final product. Over the past few years, numerous efforts have been made for efficient synthesis of boryl radicals and the expansion of substrate scope of the radical hydroboration reaction. Here, we discuss the recent advancement of radical hydroboration and its associated mechanisms. Numerous radical hydroboration strategies employing N-heterocyclic carbene borane, bis(pinacolato)diboron and pinacolborane as the boron source were illustrated. Thermochemical, photochemical and electrochemical strategies for the generation of boryl radicals were also discussed in detail.
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Affiliation(s)
- Yee Lin Phang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Ji-Kang Jin
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Feng-Lian Zhang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Yi-Feng Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
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6
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Zeng J, You F, Zhu J. Screening seven-electron boron-centered radicals for dinitrogen activation. J Comput Chem 2024; 45:648-654. [PMID: 38073508 DOI: 10.1002/jcc.27281] [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: 09/09/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 03/02/2024]
Abstract
The activation of dinitrogen is significant as nitrogen-containing compounds play an important role in industries. However, the inert NN triple bond caused by its large HOMO-LUMO gap (10.8 eV) and high bond dissociation energy (945 kJ mol-1 ) renders its activation under mild conditions particularly challenging. Recent progress shows that a few main group species can mimic transition metal complexes to activate dinitrogen. Here, we demonstrate that a series of seven-electron (7e) boron-centered radical can be used to activate N2 via density functional theory calculations. It is found that boron-centered radicals containing amine ligand perform best on the thermodynamics of dinitrogen activation. In addition, when electron-donating groups are introduced at the boron atom, these radicals can be used to activate N2 with low reaction barriers. Further analysis suggests that the electron transfer from the boron atom to the π* orbitals of dinitrogen is essential for its activation. Our findings suggest great potential of 7e boron radicals in the field of dinitrogen activation.
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Affiliation(s)
- Jie Zeng
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, China
- Pharmaceutical Research Institute, Wuhan Institute of Technology, Wuhan, China
| | - Feiying You
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Jun Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, China
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
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7
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Nagy B, Gonda Z, Földesi T, Fehér PP, Stirling A, Tolnai GL, Novák Z. Photoinduced Decarboxylative Borylation of N-Hydroxyphthalimide Esters with Hypoboric Acid. Org Lett 2024; 26:2292-2296. [PMID: 38477500 DOI: 10.1021/acs.orglett.4c00511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
We developed a visible-light-driven photochemical transformation in which activated primary, secondary, and tertiary alkylcarboxylic acids were converted into the corresponding boronic esters in the absence of catechol and any added photocatalyst. The procedure relies on the utilization of hypoboric acid and redox-active esters of alkylcarboxylic acids to ensure a simple and economic procedure. Quantum chemical calculations and mechanistic considerations provide deeper insights into the mechanism of photochemical borylation reactions.
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Affiliation(s)
- Bálint Nagy
- MTA-ELTE "Lendület" Catalysis and Organic Synthesis Research Group, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Zsombor Gonda
- MTA-ELTE "Lendület" Catalysis and Organic Synthesis Research Group, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
- ELTE Novel Scaffolds Research Group, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Tamás Földesi
- MTA-ELTE "Lendület" Catalysis and Organic Synthesis Research Group, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Péter Pál Fehér
- Research Centre for Natural Sciences, HUN-REN, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary
| | - András Stirling
- Research Centre for Natural Sciences, HUN-REN, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary
- Department of Chemistry, Eszterházy Károly Catholic University, Leányka u. 6, H-3300 Eger, Hungary
| | - Gergely L Tolnai
- ELTE Novel Scaffolds Research Group, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Zoltán Novák
- MTA-ELTE "Lendület" Catalysis and Organic Synthesis Research Group, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
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8
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Xie Y, Zhang R, Chen Z, Rong M, He H, Ni S, He X, Xiao W, Xuan J. Photocatalytic Boryl Radicals Triggered Sequential B─N/C─N Bond Formation to Assemble Boron-Handled Pyrazoles. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306728. [PMID: 38018506 PMCID: PMC10797447 DOI: 10.1002/advs.202306728] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/26/2023] [Indexed: 11/30/2023]
Abstract
Vinyldiazo compounds are one of the most important synthons in the construction of a cyclic ring. Most photochemical transformations of vinyldiazo compounds are mainly focusing on utilization of their C═C bond site, while reactions taking place at terminal nitrogen atom are largely unexplored. Herein, a photocatalytic cascade radical cyclization of LBRs with vinyldiazo reagents through sequential B─N/C─N bond formation is described. The reaction starts with the addition of LBRs (Lewis base-boryl radicals) at diazo site, followed by intramolecular radical cyclization to access a wide range of important boron-handled pyrazoles in good to excellent yields. Control experiments, together with detailed mechanism studies well explain the observed reactivity. Further studies demonstrate the utility of this approach for applications in pharmaceutical and agrochemical research.
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Affiliation(s)
- Yang Xie
- Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Key Laboratory of Functional Inorganic Materials of Anhui ProvinceCollege of Chemistry & Chemical EngineeringAnhui UniversityHefeiAnhui230601P. R. China
| | - Ruilong Zhang
- Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Key Laboratory of Functional Inorganic Materials of Anhui ProvinceCollege of Chemistry & Chemical EngineeringAnhui UniversityHefeiAnhui230601P. R. China
| | - Ze‐Le Chen
- Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Key Laboratory of Functional Inorganic Materials of Anhui ProvinceCollege of Chemistry & Chemical EngineeringAnhui UniversityHefeiAnhui230601P. R. China
| | - Mengtao Rong
- Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Key Laboratory of Functional Inorganic Materials of Anhui ProvinceCollege of Chemistry & Chemical EngineeringAnhui UniversityHefeiAnhui230601P. R. China
| | - Hui He
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong ProvinceShantou UniversityShantouGuangdong515063P. R. China
| | - Shaofei Ni
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong ProvinceShantou UniversityShantouGuangdong515063P. R. China
| | - Xiang‐Kui He
- Key Laboratory of Pesticide and Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhanHubei430079P. R. China
| | - Wen‐Jing Xiao
- Key Laboratory of Pesticide and Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhanHubei430079P. R. China
| | - Jun Xuan
- Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Key Laboratory of Functional Inorganic Materials of Anhui ProvinceCollege of Chemistry & Chemical EngineeringAnhui UniversityHefeiAnhui230601P. R. China
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9
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Yue F, Ma H, Ding P, Song H, Liu Y, Wang Q. Formation of C-B, C-C, and C-X Bonds from Nonstabilized Aryl Radicals Generated from Diaryl Boryl Radicals. ACS CENTRAL SCIENCE 2023; 9:2268-2276. [PMID: 38161365 PMCID: PMC10755731 DOI: 10.1021/acscentsci.3c00993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/14/2023] [Accepted: 10/30/2023] [Indexed: 01/03/2024]
Abstract
With the development of organoboron chemistry, boron-centered radicals have become increasingly attractive. However, their synthetic applications remain limited in that they have been used only as substrates for addition reactions or as initiators for catalytic reactions. We have achieved a new reaction pathway in which tetraarylborate salts are used as precursors for aryl radicals via boron radicals, by introducing a simple activation reagent. In addition, we carried out a diverse array of transformations involving these aryl radical precursors, which allowed the construction of new C-B, C-C, and C-X bonds in the presence of visible light.
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Affiliation(s)
- Fuyang Yue
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Henan Ma
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Pengxuan Ding
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Hongjian Song
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Yuxiu Liu
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Qingmin Wang
- State Key Laboratory of Elemento-Organic
Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers
Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
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10
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Biremond T, Riomet M, Jubault P, Poisson T. Photocatalytic and Electrochemical Borylation and Silylation Reactions. CHEM REC 2023; 23:e202300172. [PMID: 37358334 DOI: 10.1002/tcr.202300172] [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: 05/10/2023] [Revised: 06/05/2023] [Indexed: 06/27/2023]
Abstract
Due to their high versatility borylated and silylated compounds are inevitable synthons for organic chemists. To escape the classical hydroboration/hydrosilylation paradigm, chemists turned their attention to more modern and green methods such as photoredox chemistry and electrosynthesis. This account focuses on novel methods for the generation of boryl and silyl radicals to forge C-B and C-Si bonds from our group.
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Affiliation(s)
- Tony Biremond
- Normandie Univ., INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France
| | - Margaux Riomet
- Normandie Univ., INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France
| | - Philippe Jubault
- Normandie Univ., INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France
| | - Thomas Poisson
- Normandie Univ., INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France
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11
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Zhang ZQ, Wang CQ, Li LJ, Piper JL, Peng ZH, Ma JA, Zhang FG, Wu J. Programmable synthesis of difluorinated hydrocarbons from alkenes through a photocatalytic linchpin strategy. Chem Sci 2023; 14:11546-11553. [PMID: 37886092 PMCID: PMC10599468 DOI: 10.1039/d3sc03951j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023] Open
Abstract
The introduction of difluoromethylene moieties into organic molecules has garnered significant attention due to their profound influence on the physicochemical and biological properties of compounds. Nonetheless, the existing approaches for accessing difluoroalkanes from readily available feedstock chemicals remain limited. In this study, we present an efficient and modular protocol for the synthesis of difluorinated compounds from alkenes, employing the readily accessible reagent, ClCF2SO2Na, as a versatile "difluoromethylene" linchpin. By means of an organophotoredox-catalysed hydrochlorodifluoromethylation of alkenes, followed by a ligated boryl radical-facilitated halogen atom transfer (XAT) process, we have successfully obtained various difluorinated compounds, including gem-difluoroalkanes, gem-difluoroalkenes, difluoromethyl alkanes, and difluoromethyl alkenes, with satisfactory yields. The practical utility of this linchpin strategy has been demonstrated through the successful preparation of CF2-linked derivatives of complex drugs and natural products. This method opens up new avenues for the synthesis of structurally diverse difluorinated hydrocarbons and highlights the utility of ligated boryl radicals in organofluorine chemistry.
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Affiliation(s)
- Zhi-Qi Zhang
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University Tianjin 300072 P. R. China
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Cheng-Qiang Wang
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Long-Ji Li
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Jared L Piper
- Pfizer Worldwide Research and Development Medicine Eastern Point Rd, Groton CT 06340 USA
| | - Zhi-Hui Peng
- Pfizer Worldwide Research and Development Medicine Eastern Point Rd, Groton CT 06340 USA
| | - Jun-An Ma
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University Tianjin 300072 P. R. China
| | - Fa-Guang Zhang
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University Tianjin 300072 P. R. China
| | - Jie Wu
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
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12
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Xie F, Mao Z, Curran DP, Liang H, Dai W. Facile Borylation of Alkenes, Alkynes, Imines, Arenes and Heteroarenes with N-Heterocyclic Carbene-Boranes and a Heterogeneous Semiconductor Photocatalyst. Angew Chem Int Ed Engl 2023; 62:e202306846. [PMID: 37555790 DOI: 10.1002/anie.202306846] [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: 05/16/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/10/2023]
Abstract
Although the development of radical chain and photocatalytic borylation reactions using N-heterocyclic carbene (NHC)-borane as boron source is remarkable, the persistent problems, including the use of hazardous and high-energy radical initiators or the recyclability and photostability issues of soluble homogeneous photocatalysts, still leave great room for further development in a sustainable manner. Herein, we report a conceptually different approach toward highly functionalized organoborane synthesis by using recoverable ultrathin cadmium sulfide (CdS) nanosheets as a heterogeneous photocatalyst, and a general and mild borylation platform that enables regioselective borylation of a wide variety of alkenes (arylethenes, trifluoromethylalkenes, α,β-unsaturated carbonyl compounds and nitriles), alkynes, imines and electron-poor aromatic rings with NHC-borane as boryl radical precursor. Mechanistic studies and density functional theory (DFT) calculations reveal that both photogenerated electrons and holes on the CdS fully perform their own roles, thereby resulting in enhancement of photocatalytic activity and stability of CdS.
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Affiliation(s)
- Fukai Xie
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Zhan Mao
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Dennis P Curran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15208, USA
| | - Hongliang Liang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Wen Dai
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
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13
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Marotta A, Fang H, Adams CE, Sun Marcus K, Daniliuc CG, Molloy JJ. Direct Light-Enabled Access to α-Boryl Radicals: Application in the Stereodivergent Synthesis of Allyl Boronic Esters. Angew Chem Int Ed Engl 2023; 62:e202307540. [PMID: 37326432 DOI: 10.1002/anie.202307540] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
Operationally simple strategies to assemble boron containing organic frameworks are highly enabling in organic synthesis. While conventional retrosynthetic logic has engendered many platforms focusing on the direct formation of C-B bonds, α-boryl radicals have recently reemerged as versatile open-shell alternatives to access organoborons via adjacent C-C bond formation. Direct light-enabled α-activation is currently contingent on photo- or transition metal-catalysis activation to efficiently generate radical species. Here, we disclose a facile activation of α-halo boronic esters using only visible light and a simple Lewis base to enable homolytic scission. Intermolecular addition to styrenes facilitates the rapid construction of highly versatile E-allylic boronic esters. The simplicity of activation permits the strategic merger of this construct with selective energy transfer catalysis to enable the complimentary stereodivergent synthesis of Z-allylic boronic esters.
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Affiliation(s)
- Alessandro Marotta
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Hao Fang
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Callum E Adams
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Kailey Sun Marcus
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - John J Molloy
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany
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14
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Wan T, Capaldo L, Ravelli D, Vitullo W, de Zwart FJ, de Bruin B, Noël T. Photoinduced Halogen-Atom Transfer by N-Heterocyclic Carbene-Ligated Boryl Radicals for C(sp 3)-C(sp 3) Bond Formation. J Am Chem Soc 2022; 145:991-999. [PMID: 36583709 PMCID: PMC9853867 DOI: 10.1021/jacs.2c10444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Herein, we present a comprehensive study on the use of N-heterocyclic carbene (NHC)-ligated boryl radicals to enable C(sp3)-C(sp3) bond formation under visible-light irradiation via Halogen-Atom Transfer (XAT). The methodology relies on the use of an acridinium dye to generate the boron-centered radicals from the corresponding NHC-ligated boranes via single-electron transfer (SET) and deprotonation. These boryl radicals subsequently engage with alkyl halides in an XAT step, delivering the desired nucleophilic alkyl radicals. The present XAT strategy is very mild and accommodates a broad scope of alkyl halides, including medicinally relevant compounds and biologically active molecules. The key role of NHC-ligated boryl radicals in the operative reaction mechanism has been elucidated through a combination of experimental, spectroscopic, and computational studies. This methodology stands as a significant advancement in the chemistry of NHC-ligated boryl radicals, which had long been restricted to radical reductions, enabling C-C bond formation under visible-light photoredox conditions.
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Affiliation(s)
- Ting Wan
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Luca Capaldo
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Davide Ravelli
- PhotoGreen
Lab, Department of Chemistry, University
of Pavia, viale Taramelli 12, 27100 Pavia, Italy
| | - Walter Vitullo
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular and Bio-inspired Catalysis Group (HomKat), van’t
Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular and Bio-inspired Catalysis Group (HomKat), van’t
Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Timothy Noël
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands,E-mail:
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15
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Aelterman M, Biremond T, Jubault P, Poisson T. Electrochemical Synthesis of gem-Difluoro- and γ-Fluoro-Allyl Boronates and Silanes. Chemistry 2022; 28:e202202194. [PMID: 36067044 PMCID: PMC9828158 DOI: 10.1002/chem.202202194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Indexed: 01/12/2023]
Abstract
The electrochemical synthesis of fluorinated allyl silanes and boronates was disclosed. The addition of electrogenerated boryl or silyl radicals onto many α-trifluoromethyl or α-difluoromethylstyrenes in an undivided cell allowed the formation of a large panel of synthetically useful gem-difluoro and γ-fluoroallyl boronates and silanes (64 examples, from 31 % to 95 % yield). In addition, a scale up of the reactions under continuous flow was showcased using an electrochemical reactor with promising volumetric productivity (688 g.L-1 .h-1 and 496 g.L-1 .h-1 ). Moreover, the synthetic utility of these building blocks was highlighted through versatile transformations. Finally, plausible reaction mechanisms were suggested to explain the formation of the products.
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Affiliation(s)
- Maude Aelterman
- Normandie Univ INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014)76000RouenFrance
| | - Tony Biremond
- Normandie Univ INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014)76000RouenFrance
| | - Philippe Jubault
- Normandie Univ INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014)76000RouenFrance
| | - Thomas Poisson
- Normandie Univ INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014)76000RouenFrance
- Institut Universitaire de France1 rue Descartes75231ParisFrance
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16
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Li X, Chen Z, Chen W, Xie X, Zhou H, Liao Y, Yu F, Huang J. B 2pin 2-Mediated Cascade Cyclization/Aromatization Reaction: Facial Access to Functionalized Indolizines. Org Lett 2022; 24:7372-7377. [PMID: 36173232 DOI: 10.1021/acs.orglett.2c02905] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Herein, a B2pin2-mediated radical cascade cyclization/aromatization reaction of enaminone with pyridine is described. This strategy provides a practical way for the construction of valuable functionalized indolizines under metal-, external oxidant-, and base-free conditions, which could be compatible with various kinds of functional groups, such as halogen, π-system, heterocycle, ferrocenyl, etc. A preliminary mechanism investigation indicated that the pyridine-boryl radical formed in situ triggered the reaction to occur.
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Affiliation(s)
- Xiaoning Li
- School of Pharmacy, Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou 341000, PR China
| | - Zunsheng Chen
- School of Pharmacy, Gannan Medical University, Ganzhou 341000, PR China
| | - Weiming Chen
- School of Pharmacy, Gannan Medical University, Ganzhou 341000, PR China
| | - Xin Xie
- School of Pharmacy, Gannan Medical University, Ganzhou 341000, PR China
| | - Hui Zhou
- School of Pharmacy, Gannan Medical University, Ganzhou 341000, PR China
| | - Yingmei Liao
- School of Pharmacy, Gannan Medical University, Ganzhou 341000, PR China
| | - Fuchao Yu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Jiuzhong Huang
- School of Pharmacy, Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou 341000, PR China
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17
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Breitwieser K, Bahmann H, Weiss R, Munz D. Gauging Radical Stabilization with Carbenes. Angew Chem Int Ed Engl 2022; 61:e202206390. [PMID: 35796423 PMCID: PMC9545232 DOI: 10.1002/anie.202206390] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Indexed: 11/29/2022]
Abstract
Carbenes, including N-heterocyclic carbene (NHC) ligands, are used extensively to stabilize open-shell transition metal complexes and organic radicals. Yet, it remains unknown, which carbene stabilizes a radical well and, thus, how to design radical-stabilizing C-donor ligands. With the large variety of C-donor ligands experimentally investigated and their electronic properties established, we report herein their radical-stabilizing effect. We show that radical stabilization can be understood by a captodative frontier orbital description involving π-donation to- and π-donation from the carbenes. This picture sheds a new perspective on NHC chemistry, where π-donor effects usually are assumed to be negligible. Further, it allows for the intuitive prediction of the thermodynamic stability of covalent radicals of main group- and transition metal carbene complexes, and the quantification of redox non-innocence.
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Affiliation(s)
- Kevin Breitwieser
- Coordination ChemistrySaarland UniversityCampus C4.166123SaarbrückenGermany
| | - Hilke Bahmann
- Physical and Theoretical ChemistrySaarland UniversityCampus B2.266123SaarbrückenGermany
| | - Robert Weiss
- Organische ChemieFriedrich-Alexander-Universität (FAU) Erlangen-NürnbergHenkestr. 4291054ErlangenGermany
| | - Dominik Munz
- Coordination ChemistrySaarland UniversityCampus C4.166123SaarbrückenGermany
- Inorganic and General ChemistryFriedrich-Alexander-Universität (FAU) Erlangen-NürnbergEgerlandstr. 191058ErlangenGermany
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18
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Chen M, Xu J, Zhao D, Sun F, Tian S, Tu D, Lu C, Yan H. Site-Selective Functionalization of Carboranes at the Electron-Rich Boron Vertex: Photocatalytic B-C Coupling via a Carboranyl Cage Radical. Angew Chem Int Ed Engl 2022; 61:e202205672. [PMID: 35670361 DOI: 10.1002/anie.202205672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Indexed: 12/14/2022]
Abstract
Functionalization of carboranes in a vertex-specific manner is a perennial challenge. Here, we report a photocatalytic B-C coupling for the selective functionalization of carboranes at the boron site which is most distal to carbon. This reaction was achieved by the photo-induced decarboxylation of carborane carboxylic acids to generate boron vertex-centered carboranyl radicals. Theoretical calculations also demonstrate that the reaction more easily occurs at the boron site bearing higher electron density owing to the lower energy barrier for a single-electron transfer to generate a carboranyl radical. By using this strategy, a number of functionalized carboranes could be accessed through alkylation, alkenylation, and heteroarylation under mild conditions. Moreover, both a highly efficient blue emitter with a solid-state luminous efficiency of 42 % and a drug candidate for boron neutron capture therapy (BNCT) containing targeting and fluorine units were obtained.
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Affiliation(s)
- Meng Chen
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Jingkai Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Deshi Zhao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Fangxiang Sun
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Songlin Tian
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Deshuang Tu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Changsheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
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19
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Breitwieser K, Bahmann H, Weiss R, Munz D. Gauging Radical Stabilization with Carbenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kevin Breitwieser
- Saarland University: Universitat des Saarlandes Coordination Chemistry GERMANY
| | - Hilke Bahmann
- Saarland University: Universitat des Saarlandes Theoretical Chemistry GERMANY
| | - Robert Weiss
- FAU Erlangen Nuremberg: Friedrich-Alexander-Universitat Erlangen-Nurnberg Organic Chemistry GERMANY
| | - Dominik Munz
- Universitat des Saarlandes Inorganic Chemistry: Coordination Chemistry Campus C 4.1 66123 Saarbrücken GERMANY
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20
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Peng TY, Xu ZY, Zhang FL, Li B, Xu WP, Fu Y, Wang YF. Dehydroxylative Alkylation of α-Hydroxy Carboxylic Acid Derivatives via a Spin-Center Shift. Angew Chem Int Ed Engl 2022; 61:e202201329. [PMID: 35388555 DOI: 10.1002/anie.202201329] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Indexed: 11/05/2022]
Abstract
A strategically distinct dehydroxylative alkylation reaction of α-hydroxy carboxylic acid derivatives with alkenes is developed. The reaction starts with the attack of a 4-dimethylaminopyridine (DMAP)-boryl radical to the carbonyl oxygen atom, followed by a spin-center shift (SCS) to trigger the C-O bond scission. The resulting α-carbonyl radicals couple with a wide range of alkenes to furnish various alkylated products. This strategy allows for the efficient conversion of a wide array of α-hydroxy amides and esters derived from several biomass molecules and natural products to value-added compounds. Experimental and computational studies verified the reaction mechanism.
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Affiliation(s)
- Tian-Yu Peng
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Zhe-Yuan Xu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Feng-Lian Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Bin Li
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Wen-Ping Xu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Yao Fu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Yi-Feng Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
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21
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Chen M, Xu J, Zhao D, Sun F, Tian S, Tu D, Lu C, Yan H. Site‐Selective Functionalization of Carboranes at Electron‐Rich Boron Vertex: Photocatalytic B‐C Coupling via a Carboranyl Cage Radical. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Meng Chen
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Jingkai Xu
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Deshi Zhao
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Fangxiang Sun
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Songlin Tian
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Deshuang Tu
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Changsheng Lu
- Nanjing University School of Chemistry and Chemical Engineering CHINA
| | - Hong Yan
- Nanjing University School of Chemistry and Chemical Engineering 22 Hankou Rd. 210093 Nanjing CHINA
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22
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Mollner TA, Giltrap AM, Zeng Y, Demyanenko Y, Buchanan C, Oehlrich D, Baldwin AJ, Anthony DC, Mohammed S, Davis BG. Reductive site-selective atypical C, Z-type/N2-C2 cleavage allows C-terminal protein amidation. SCIENCE ADVANCES 2022; 8:eabl8675. [PMID: 35394836 PMCID: PMC8993120 DOI: 10.1126/sciadv.abl8675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Biomolecule environments can enhance chemistries with the potential to mediate and modulate self-modification (e.g., self-cleavage). While these enhanced modes are found in certain biomolecules (e.g., RNA ribozymes), it is more rare in proteins. Targeted proteolytic cleavage is vital to physiology, biotechnology, and even emerging therapy. Yet, purely chemically induced methods for the site-selective cleavage of proteins remain scarce. Here, as a proof of principle, we designed and tested a system intended to combine protein-enhanced chemistry with tag modification to enable synthetic reductive protein chemistries promoted by diboron. This reductively driven, single-electron chemistry now enables an operationally simple, site-selective cleavage protocol for proteins directed to readily accessible dehydroalanine (Dha) residues as tags under aqueous conditions and in cell lysates. In this way, a mild, efficient, enzyme-free method now allows not only precise chemical proteolysis but also simultaneous use in the removal of affinity tags and/or protein-terminus editing to create altered N- and C-termini such as protein amidation (─CONH2).
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Affiliation(s)
- Tim A. Mollner
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | | | - Yibo Zeng
- The Rosalind Franklin Institute, Oxfordshire, UK
| | | | - Charles Buchanan
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Daniel Oehlrich
- Global Medicinal Chemistry, Janssen Research & Development, Beerse, Belgium
| | - Andrew J. Baldwin
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- The Rosalind Franklin Institute, Oxfordshire, UK
| | | | - Shabaz Mohammed
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- The Rosalind Franklin Institute, Oxfordshire, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Benjamin G. Davis
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- The Rosalind Franklin Institute, Oxfordshire, UK
- Department of Pharmacology, University of Oxford, Oxford, UK
- Corresponding author.
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23
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Peng TY, Xu ZY, Zhang FL, Li B, Xu WP, Fu Y, Wang YF. Dehydroxylative Alkylation of α‐Hydroxy Carboxylic Acids Derivatives via Spin‐center Shift. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Tian-Yu Peng
- University of Science and Technology of China Department of Chemistry CHINA
| | - Zhe-Yuan Xu
- University of Science and Technology of China Department of Chemistry CHINA
| | - Feng-Lian Zhang
- University of Science and Technology of China Department of Chemistry CHINA
| | - Bin Li
- University of Science and Technology of China Department of Chemistry CHINA
| | - Wen-Ping Xu
- University of Science and Technology of China Department of Chemistry CHINA
| | - Yao Fu
- University of Science and Technology of China Department of Chemistry CHINA
| | - Yi-Feng Wang
- University of Science and Technology of China Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry 96 Jinzhai Road 230026 Hefei CHINA
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24
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Li WD, Wu Y, Li SJ, Jiang YQ, Li YL, Lan Y, Xia JB. Boryl Radical Activation of Benzylic C-OH Bond: Cross-Electrophile Coupling of Free Alcohols and CO 2 via Photoredox Catalysis. J Am Chem Soc 2022; 144:8551-8559. [PMID: 35378034 DOI: 10.1021/jacs.1c12463] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A new strategy for the direct cleavage of the C(sp3)-OH bond has been developed via activation of free alcohols with neutral diphenyl boryl radical generated from sodium tetraphenylborate under mild visible light photoredox conditions. This strategy has been verified by cross-electrophile coupling of free alcohols and carbon dioxide for the synthesis of carboxylic acids. Direct transformation of a range of primary, secondary, and tertiary benzyl alcohols to acids has been achieved. Control experiments and computational studies indicate that activation of alcohols with neutral boryl radical undergoes homolysis of the C(sp3)-OH bond, generating alkyl radicals. After reducing the alkyl radical into carbon anion under photoredox conditions, the following carboxylation with CO2 affords the coupling product.
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Affiliation(s)
- Wen-Duo Li
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Lanzhou Institute of Chemical Physics (LICP), University of Chinese Academy of Sciences, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yang Wu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Lanzhou Institute of Chemical Physics (LICP), University of Chinese Academy of Sciences, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Shi-Jun Li
- College of Chemistry, and Institute of Green Catalysis, Zhengzhou University, 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Yi-Qian Jiang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Lanzhou Institute of Chemical Physics (LICP), University of Chinese Academy of Sciences, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yan-Lin Li
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Lanzhou Institute of Chemical Physics (LICP), University of Chinese Academy of Sciences, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yu Lan
- College of Chemistry, and Institute of Green Catalysis, Zhengzhou University, 100 Science Avenue, Zhengzhou, Henan 450001, China.,School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 400030, China
| | - Ji-Bao Xia
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Lanzhou Institute of Chemical Physics (LICP), University of Chinese Academy of Sciences, Chinese Academy of Sciences, Lanzhou 730000, China
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25
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Pajk SP, Qi Z, Sujansky SJ, Bandar JS. A Base-Catalyzed Approach for the anti-Markovnikov Hydration of Styrene Derivatives. Chem Sci 2022; 13:11427-11432. [PMID: 36320585 PMCID: PMC9533481 DOI: 10.1039/d2sc02827a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/24/2022] [Indexed: 11/21/2022] Open
Abstract
The base-catalyzed addition of 1-cyclopropylethanol to styrene derivatives with an acidic reaction workup enables anti-Markovnikov hydration. The use of either catalytic organic superbase or crown ether-ligated inorganic base permits hydration of a wide variety of styrene derivatives, including electron-deficient, ortho-substituted and heteroaryl variants. This protocol complements alternative routes to terminal alcohols that rely on stoichiometric reduction and oxidation processes. The utility of this method is demonstrated through multigram scale reactions and its use in a two-step hydration/cyclization process of ortho-halogenated styrenes to prepare 2,3-dihydrobenzofuran derivatives. The base-catalyzed addition of 1-cyclopropylethanol to vinyl (hetero)arenes sequenced with an acidic reaction workup enables anti-Markovnikov hydration in a complementary fashion to traditional hydroboration/oxidation protocols.![]()
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Affiliation(s)
- Spencer P Pajk
- Department of Chemistry, Colorado State University Fort Collins Colorado 80523 USA
| | - Zisong Qi
- Department of Chemistry, Colorado State University Fort Collins Colorado 80523 USA
| | - Stephen J Sujansky
- Department of Chemistry, Colorado State University Fort Collins Colorado 80523 USA
| | - Jeffrey S Bandar
- Department of Chemistry, Colorado State University Fort Collins Colorado 80523 USA
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Chen C, Daniliuc CG, Klabunde S, Hansen MR, Kehr G, Erker G. Generation of Boryl-nitroxide Radicals from a Boraalkene via the Nitroso Ene Reaction. Chem Sci 2022; 13:10891-10896. [PMID: 36320693 PMCID: PMC9491209 DOI: 10.1039/d2sc02485c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/09/2022] [Indexed: 11/21/2022] Open
Abstract
Examples of isolated boron substituted nitroxide radicals are rare. The reaction of the reactive cyclic boraalkene 3 with nitrosobenzene yields a mixture of the [2 + 2] cycloaddition product 4a, the B-nitroxide radicals 5a and 6a and the azoxybenzene co-product 7avia a bora nitroso ene reaction pathway, the boron analogue of the nitroso ene reaction. The products were separated by flash chromatography, and the B-nitroxide radicals were characterized by X-ray diffraction and EPR spectroscopy. Radical 5a was shown to be a hydrogen atom abstractor. Both the B-nitroxide radicals are more easily oxidized compared to e.g. TEMPO, as shown by cyclic voltammetry. The NHC-stabilized boraalkene reacts with nitrosobenzene to give a [2+2] cycloaddition product plus a pair of persistent borylnitroxide radicals. These are thought to be formed by means of a bora nitroso ene reaction followed by H-atom transfer.![]()
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Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Sina Klabunde
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster Corrensstraße 28/3040 48149 Münster Germany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster Corrensstraße 28/3040 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
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Kuehn L, Zapf L, Werner L, Stang M, Würtemberger-Pietsch S, Krummenacher I, Braunschweig H, Lacôte E, Marder TB, Radius U. NHC induced radical formation via homolytic cleavage of B–B bonds and its role in organic reactions. Chem Sci 2022; 13:8321-8333. [PMID: 35919710 PMCID: PMC9297536 DOI: 10.1039/d2sc02096c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/07/2022] [Indexed: 11/21/2022] Open
Abstract
New borylation methodologies have been reported recently, wherein diboron(4) compounds apparently participate in free radical couplings via the homolytic cleavage of the B–B bond. We report herein that bis-NHC adducts of the type (NHC)2·B2(OR)4, which are thermally unstable and undergo intramolecular ring expansion reactions (RER), are sources of boryl radicals of the type NHC–BR2˙, exemplified by Me2ImMe·Bneop˙ 1a (Me2ImMe = 1,3,4,5-tetramethyl-imidazolin-2-ylidene, neop = neopentylglycolato), which are formed by homolytic B–B bond cleavage. Attempts to apply the boryl moiety 1a in a metal-free borylation reaction by suppressing the RER failed. However, based on these findings, a protocol was developed using Me2ImMe·B2pin23 for the transition metal- and additive-free boryl transfer to substituted aryl iodides and bromides giving aryl boronate esters in good yields. Analysis of the side products and further studies concerning the reaction mechanism revealed that radicals are likely involved. An aryl radical was trapped by TEMPO, an EPR resonance, which was suggestive of a boron-based radical, was detected in situ, and running the reaction in styrene led to the formation of polystyrene. The isolation of a boronium cation side product, [(Me2ImMe)2·Bpin]+I−7, demonstrated the fate of the second boryl moiety of B2pin2. Interestingly, Me2ImMe NHC reacts with aryl iodides and bromides generating radicals. A mechanism for the boryl radical transfer from Me2ImMe·B2pin23 to aryl iodides and bromides is proposed based on these experimental observations. Bis-NHC adducts of the type (NHC)2·B2(OR)4 are sources of boryl radicals of the type NHC–BR2˙, which are formed by homolytic B–B bond cleavage.![]()
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Affiliation(s)
- Laura Kuehn
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Ludwig Zapf
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Luis Werner
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Martin Stang
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Sabrina Würtemberger-Pietsch
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Emmanuel Lacôte
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, Bât. Raulin, 2 rue Victor Grignard, F-69622 Villeurbanne, France
| | - Todd B. Marder
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Udo Radius
- Institute for Inorganic Chemistry, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Deis T, Medici F, Poussard-Schulz A, Lemière G, Fensterbank L. Synthesis and reactivity of an anionic NHC-borane featuring a weakly coordinating silicate anion. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.122120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Bose SK, Mao L, Kuehn L, Radius U, Nekvinda J, Santos WL, Westcott SA, Steel PG, Marder TB. First-Row d-Block Element-Catalyzed Carbon-Boron Bond Formation and Related Processes. Chem Rev 2021; 121:13238-13341. [PMID: 34618418 DOI: 10.1021/acs.chemrev.1c00255] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Organoboron reagents represent a unique class of compounds because of their utility in modern synthetic organic chemistry, often affording unprecedented reactivity. The transformation of the carbon-boron bond into a carbon-X (X = C, N, and O) bond in a stereocontrolled fashion has become invaluable in medicinal chemistry, agrochemistry, and natural products chemistry as well as materials science. Over the past decade, first-row d-block transition metals have become increasingly widely used as catalysts for the formation of a carbon-boron bond, a transformation traditionally catalyzed by expensive precious metals. This recent focus on alternative transition metals has enabled growth in fundamental methods in organoboron chemistry. This review surveys the current state-of-the-art in the use of first-row d-block element-based catalysts for the formation of carbon-boron bonds.
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Affiliation(s)
- Shubhankar Kumar Bose
- Centre for Nano and Material Sciences (CNMS), Jain University, Jain Global Campus, Bangalore-562112, India
| | - Lujia Mao
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, 571199 Haikou, Hainan, P. R. China
| | - Laura Kuehn
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Udo Radius
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jan Nekvinda
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Webster L Santos
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Stephen A Westcott
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G8, Canada
| | - Patrick G Steel
- Department of Chemistry, University of Durham, Science Laboratories South Road, Durham DH1 3LE, U.K
| | - Todd B Marder
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Abstract
Boron-centred radicals (boryl radicals) are potential and attractive species in main group chemistry and synthetic chemistry. Recently, the development of boron compounds ligated by N-heterocyclic carbenes (NHCs) has sparked off advavnces in boryl radical chemistry because NHCs can highly stabilise boryl radicals by electronic and steric factors. This review highlights recent synthesis and reactions of such NHC-boryl radicals. From the standpoint of main group chemistry, examples of isolation or detection of unique NHC-boryl radicals are presented. From the standpoint of synthetic chemistry, on the other hand, the development of reactions of user-friendly NHC-boryl radicals, which has contributed to radical chemistry, organoboron chemistry and polymer science, is comprehensively described.
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Affiliation(s)
- Tsuyoshi Taniguchi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
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31
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Lei G, Xu M, Chang R, Funes-Ardoiz I, Ye J. Hydroalkylation of Unactivated Olefins via Visible-Light-Driven Dual Hydrogen Atom Transfer Catalysis. J Am Chem Soc 2021; 143:11251-11261. [PMID: 34269582 DOI: 10.1021/jacs.1c05852] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Radical hydroalkylation of olefins enabled by hydrogen atom transfer (HAT) catalysis represents a straightforward means to access C(sp3)-rich molecules from abundant feedstock chemicals without the need for prefunctionalization. While Giese-type hydroalkylation of activated olefins initiated by HAT of hydridic carbon-hydrogen bonds is well-precedented, hydroalkylation of unactivated olefins in a similar fashion remains elusive, primarily owing to a lack of general methods to overcome the inherent polarity-mismatch in this scenario. Here, we report the use of visible-light-driven dual HAT catalysis to achieve this goal, where catalytic amounts of an amine-borane and an in situ generated thiol were utilized as the hydrogen atom abstractor and donor, respectively. The reaction is completely atom-economical and exhibits a broad scope. Experimental and computational studies support the proposed mechanism and suggest that hydrogen-bonding between the amine-borane and substrates is beneficial to improving the reaction efficiency.
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Affiliation(s)
- Guangyue Lei
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Meichen Xu
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Chang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ignacio Funes-Ardoiz
- Department of Chemistry, Centro de Investigación en Síntesis Química (CISQ), Universidad de La Rioja, Madre de Dios 53, 26006 Logroño, Spain
| | - Juntao Ye
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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33
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A radical approach for the selective C-H borylation of azines. Nature 2021; 595:677-683. [PMID: 34015802 DOI: 10.1038/s41586-021-03637-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 05/12/2021] [Indexed: 02/04/2023]
Abstract
Boron functional groups are often introduced in place of aromatic carbon-hydrogen bonds to expedite small-molecule diversification through coupling of molecular fragments1-3. Current approaches based on transition-metal-catalysed activation of carbon-hydrogen bonds are effective for the borylation of many (hetero)aromatic derivatives4,5 but show narrow applicability to azines (nitrogen-containing aromatic heterocycles), which are key components of many pharmaceutical and agrochemical products6. Here we report an azine borylation strategy using stable and inexpensive amine-borane7 reagents. Photocatalysis converts these low-molecular-weight materials into highly reactive boryl radicals8 that undergo efficient addition to azine building blocks. This reactivity provides a mechanistically alternative tactic for sp2 carbon-boron bond assembly, where the elementary steps of transition-metal-mediated carbon-hydrogen bond activation and reductive elimination from azine-organometallic intermediates are replaced by a direct, Minisci9-style, radical addition. The strongly nucleophilic character of the amine-boryl radicals enables predictable and site-selective carbon-boron bond formation by targeting the azine's most activated position, including the challenging sites adjacent to the basic nitrogen atom. This approach enables access to aromatic sites that elude current strategies based on carbon-hydrogen bond activation, and has led to borylated materials that would otherwise be difficult to prepare. We have applied this process to the introduction of amine-borane functionalities to complex and industrially relevant products. The diversification of the borylated azine products by mainstream cross-coupling technologies establishes aromatic amino-boranes as a powerful class of building blocks for chemical synthesis.
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34
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Radical philicity and its role in selective organic transformations. Nat Rev Chem 2021; 5:486-499. [PMID: 37118440 DOI: 10.1038/s41570-021-00284-3] [Citation(s) in RCA: 140] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2021] [Indexed: 12/11/2022]
Abstract
Radical intermediates in organic chemistry lack a full octet of electrons and, thus, are commonly said to be electron deficient. By denotation, such a statement is technically correct; however, in modern literature, the term 'electron deficient' carries a connotation of electrophilicity. This lexical quirk leads one to predict that all radicals should behave as electrophiles, when this is not the case. Indeed, practitioners of radical chemistry have known for decades that many radicals behave as nucleophiles, sometimes strongly so. This Review aims to establish guidelines for understanding radical philicity by highlighting examples from recent literature as a demonstration of general reactivity paradigms across a series of different carbon-based and heteroatom-based radicals. We present strategies for predicting the philicity of a given radical on the basis of qualitative features of the radical's structure. Finally, we discuss the implications of radical philicity to selective hydrogen atom transfer.
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35
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Zhong M, Gagné Y, Hope TO, Pannecoucke X, Frenette M, Jubault P, Poisson T. Copper-Photocatalyzed Hydroboration of Alkynes and Alkenes. Angew Chem Int Ed Engl 2021; 60:14498-14503. [PMID: 33780588 PMCID: PMC8252632 DOI: 10.1002/anie.202101874] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/27/2021] [Indexed: 11/23/2022]
Abstract
The photocatalytic hydroboration of alkenes and alkynes is reported. The use of newly-designed copper photocatalysts with B2 Pin2 permits the formation a boryl radical, which is used for hydroboration of a large panel of alkenes and alkynes. The hydroborated products were isolated in high yields, with excellent diastereoselectivities and a high functional group tolerance under mild conditions. The hydroboration reactions were developed under continuous flow conditions to demonstrate their synthetic utility. The reaction mechanism was studied and suggested an oxidation reaction between an in situ formed borate and the Cu-photocatalyst in its excited state for the boryl radical formation.
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Affiliation(s)
- Mingbing Zhong
- Normandie Univ.INSA RouenUNIROUENCNRSCOBRA (UMR 6014)76000RouenFrance
| | - Yohann Gagné
- Département de ChimieUniversité du Québec à MontréalCase postal 8888, Succursale Centre-VilleMontréalQuébecH3C 3P8Canada
| | - Taylor O. Hope
- Département de ChimieUniversité du Québec à MontréalCase postal 8888, Succursale Centre-VilleMontréalQuébecH3C 3P8Canada
| | | | - Mathieu Frenette
- Département de ChimieUniversité du Québec à MontréalCase postal 8888, Succursale Centre-VilleMontréalQuébecH3C 3P8Canada
| | - Philippe Jubault
- Normandie Univ.INSA RouenUNIROUENCNRSCOBRA (UMR 6014)76000RouenFrance
| | - Thomas Poisson
- Normandie Univ.INSA RouenUNIROUENCNRSCOBRA (UMR 6014)76000RouenFrance
- Institut Universitaire de France1 rue Descartes75231ParisFrance
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Zhong M, Gagné Y, Hope TO, Pannecoucke X, Frenette M, Jubault P, Poisson T. Copper‐Photocatalyzed Hydroboration of Alkynes and Alkenes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101874] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Mingbing Zhong
- Normandie Univ. INSA Rouen UNIROUEN CNRS COBRA (UMR 6014) 76000 Rouen France
| | - Yohann Gagné
- Département de Chimie Université du Québec à Montréal Case postal 8888, Succursale Centre-Ville Montréal Québec H3C 3P8 Canada
| | - Taylor O. Hope
- Département de Chimie Université du Québec à Montréal Case postal 8888, Succursale Centre-Ville Montréal Québec H3C 3P8 Canada
| | - Xavier Pannecoucke
- Normandie Univ. INSA Rouen UNIROUEN CNRS COBRA (UMR 6014) 76000 Rouen France
| | - Mathieu Frenette
- Département de Chimie Université du Québec à Montréal Case postal 8888, Succursale Centre-Ville Montréal Québec H3C 3P8 Canada
| | - Philippe Jubault
- Normandie Univ. INSA Rouen UNIROUEN CNRS COBRA (UMR 6014) 76000 Rouen France
| | - Thomas Poisson
- Normandie Univ. INSA Rouen UNIROUEN CNRS COBRA (UMR 6014) 76000 Rouen France
- Institut Universitaire de France 1 rue Descartes 75231 Paris France
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Aelterman M, Sayes M, Jubault P, Poisson T. Electrochemical Hydroboration of Alkynes. Chemistry 2021; 27:8277-8282. [PMID: 33945175 PMCID: PMC8251609 DOI: 10.1002/chem.202101132] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Indexed: 12/21/2022]
Abstract
Herein we reported the electrochemical hydroboration of alkynes by using B2Pin2 as the boron source. This unprecedented reaction manifold was applied to a broad range of alkynes, giving the hydroboration products in good to excellent yields without the need of a metal catalyst or a hydride source. This transformation relied on the possible electrochemical oxidation of an in situ formed borate. This anodic oxidation performed in an undivided cell allowed the formation of a putative boryl radical, which reacted on the alkyne.
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Affiliation(s)
- Maude Aelterman
- Normandie Université, INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France
| | - Morgane Sayes
- Centre in Green Chemistry and Catalysis, Faculty of Arts and Sciences, Department of Chemistry, Université de Montréal, P.O. Box 6128, Station Downtown, Montréal, Québec, H3 C3 J7, Canada
| | - Philippe Jubault
- Normandie Université, INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France
| | - Thomas Poisson
- Normandie Université, INSA Rouen, UNIROUEN, CNRS, COBRA (UMR 6014), 76000, Rouen, France.,Institut Universitaire de France, 1 rue Descartes, 75231, Paris, France
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Bamford KL, Qu Z, Stephan DW. Reactions of B 2 (o-tolyl) 4 with Boranes: Assembly of the Pentaborane(9), HB[B(o-tolyl)(μ-H)] 4. Angew Chem Int Ed Engl 2021; 60:8532-8536. [PMID: 33539608 PMCID: PMC8048642 DOI: 10.1002/anie.202101054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Indexed: 12/11/2022]
Abstract
Reactions of the diborane(4) B2 (o-tolyl)4 and monohydridoboranes are shown to give B(o-tolyl)3 and (o-tolyl)BR2 (R2 =(C8 H14 ) 3, cat 4, pin 5, (C6 F5 )2 6) as the major products. The corresponding reaction with BH3 -sources gives complex mixtures, resulting from hydride/aryl exchange, dimerization and borane elimination. This led to the isolation of the first tetra-substituted pentaborane(9) HB[B(o-tolyl)(μ-H)]4 8. The reaction pathways are probed experimentally and by computations.
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Affiliation(s)
- Karlee L. Bamford
- Department of ChemistryUniversity of Toronto80 St. George St.TorontoOntarioM5S3H6Canada
| | - Zheng‐Wang Qu
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieRheinische Friedrich-Wilhelms-Universität BonnBeringstrasse 453115BonnGermany
| | - Douglas W. Stephan
- Department of ChemistryUniversity of Toronto80 St. George St.TorontoOntarioM5S3H6Canada
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Liu Y, Li JL, Liu XG, Wu JQ, Huang ZS, Li Q, Wang H. Radical Borylative Cyclization of Isocyanoarenes with N-Heterocyclic Carbene Borane: Synthesis of Borylated Aza-arenes. Org Lett 2021; 23:1891-1897. [PMID: 33591193 DOI: 10.1021/acs.orglett.1c00309] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Borylated aza-arenes are of great importance in the area of organic synthesis. A radical borylative cyclization of isocyanoarenes with N-heterocyclic carbene borane (NHC-BH3) under metal-free conditions was developed. The reaction allows the efficient assembly of several types of borylated aza-arenes (phenanthridines, benzothiazoles, etc.), which are difficult to access using alternative methods. Mild reaction conditions, a good functional-group tolerance, and generally good efficiencies were observed. The utility of these products is demonstrated, and the mechanism is discussed.
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Affiliation(s)
- Yao Liu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Ji-Lin Li
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Xu-Ge Liu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Jia-Qiang Wu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhi-Shu Huang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Qingjiang Li
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Honggen Wang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
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Kawamoto T, Morioka T, Noguchi K, Curran DP, Kamimura A. Inverse Hydroboration of Imines with NHC-Boranes Is Promoted by Diphenyl Disulfide and Visible Light. Org Lett 2021; 23:1825-1828. [PMID: 33621108 DOI: 10.1021/acs.orglett.1c00230] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We describe a simple and efficient procedure for nucleophilic borylation of imines in the absence of a photoredox catalyst. Visible light irradiation of an acetonitrile solution of an imine, an NHC-borane, and diphenyl disulfide (10 mol %) provides various stable α-amino NHC-boranes in good yields. The reaction proceeds via addition of a nucleophilic boryl radical to an imine, followed by hydrogen abstraction from thiophenol, which is generated from NHC-borane and diphenyl disulfide.
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Affiliation(s)
- Takuji Kawamoto
- Department of Applied Chemistry, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan
| | - Tsubasa Morioka
- Department of Applied Chemistry, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan
| | - Kohki Noguchi
- Department of Applied Chemistry, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan
| | - Dennis P Curran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Akio Kamimura
- Department of Applied Chemistry, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan
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41
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Yu YJ, Zhang FL, Peng TY, Wang CL, Cheng J, Chen C, Houk KN, Wang YF. Sequential C-F bond functionalizations of trifluoroacetamides and acetates via spin-center shifts. Science 2021; 371:1232-1240. [PMID: 33674411 DOI: 10.1126/science.abg0781] [Citation(s) in RCA: 145] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/09/2021] [Indexed: 12/21/2022]
Abstract
Defluorinative functionalization of readily accessible trifluoromethyl groups constitutes an economical route to partially fluorinated molecules. However, the controllable replacement of one or two fluorine atoms while maintaining high chemoselectivity remains a formidable challenge. Here we describe a general strategy for sequential carbon-fluorine (C-F) bond functionalizations of trifluoroacetamides and trifluoroacetates. The reaction begins with the activation of a carbonyl oxygen atom by a 4-dimethylaminopyridine-boryl radical, followed by a spin-center shift to trigger the C-F bond scission. A chemoselectivity-controllable two-stage process enables sequential generation of difluoro- and monofluoroalkyl radicals, which are selectively functionalized with different radical traps to afford diverse fluorinated products. The reaction mechanism and the origin of chemoselectivity were established by experimental and computational approaches.
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Affiliation(s)
- You-Jie Yu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Feng-Lian Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tian-Yu Peng
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chang-Ling Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jie Cheng
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chen Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Yi-Feng Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.,Center for Excellence in Molecular Synthesis of CAS, Hefei, Anhui 230026, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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42
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Bamford KL, Qu Z, Stephan DW. Reactions of B
2
(
o
‐tolyl)
4
with Boranes: Assembly of the Pentaborane(9), HB[B(
o
‐tolyl)(μ‐H)]
4. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Karlee L. Bamford
- Department of Chemistry University of Toronto 80 St. George St. Toronto Ontario M5S3H6 Canada
| | - Zheng‐Wang Qu
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Rheinische Friedrich-Wilhelms-Universität Bonn Beringstrasse 4 53115 Bonn Germany
| | - Douglas W. Stephan
- Department of Chemistry University of Toronto 80 St. George St. Toronto Ontario M5S3H6 Canada
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43
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Tian YM, Guo XN, Braunschweig H, Radius U, Marder TB. Photoinduced Borylation for the Synthesis of Organoboron Compounds. Chem Rev 2021; 121:3561-3597. [PMID: 33596057 DOI: 10.1021/acs.chemrev.0c01236] [Citation(s) in RCA: 137] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Organoboron compounds have important synthetic value and can be applied in numerous transformations. The development of practical and convenient ways to synthesize boronate esters has thus attracted significant interest. Photoinduced borylations originated from stoichiometric reactions of alkanes and arenes with well-defined metal-boryl complexes. Now, photoredox-initiated borylations, catalyzed by either transition metal or organic photocatalysts, and photochemical borylations with high efficiency have become a burgeoning area of research. In this Focus Review, we summarize research on photoinduced borylations, especially emphasizing recent developments and trends. This includes the photoinduced borylation of arenes, alkanes, aryl/alkyl halides, activated carboxylic acids, amines, alcohols, and so on based on transition metal catalysis, metal-free organocatalysis, and direct photochemical activation. We focus on reaction mechanisms involving single-electron transfer, triplet-energy transfer, and other radical processes.
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Affiliation(s)
- Ya-Ming Tian
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Xiao-Ning Guo
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Udo Radius
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Todd B Marder
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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44
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Takahashi K, Geib SJ, Maeda K, Curran DP, Taniguchi T. Radical trans-Hydroboration of Substituted 1,3-Diynes with an N-Heterocyclic Carbene Borane. Org Lett 2021; 23:1071-1075. [PMID: 33481616 DOI: 10.1021/acs.orglett.0c04284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Monohydroboration of substituted 1,3-diynes with an N-heterocyclic carbene borane (NHC-borane) occurs under radical conditions using an azo initiator, such as ACCN and AIBN, and a thiol as a polarity-reversal catalyst. The reaction is highly regio- and stereoselective and provides stable NHC-(E)-alkynylalkenylboranes.
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Affiliation(s)
| | - Steven J Geib
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | | | - Dennis P Curran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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45
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Huang Y, Jin X, Zhang F, Wang Y. 4-Dimethylaminopyridine-Boryl Radical Promoted Regioselective Radical Hydroboration of Electron-Deficient Alkenes. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202103041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Zhu C, Gao S, Li W, Zhu C. Photoredox radical borylation of electron-deficient alkenes with NHC-boranes. Chem Commun (Camb) 2020; 56:15647-15650. [PMID: 33284913 DOI: 10.1039/d0cc06966c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
An efficient photoredox radical borylation of electron-deficient Morita-Baylis-Hillman type alkenes is achieved to afford multi-functionalized allylic boranes. The reaction demonstrates a wide substrate scope and showcases excellent functional group tolerance. It has advantages over the traditional ionic hydroboration methods in the construction of allylic boranes in terms of simple operation, mild conditions, and step-economy.
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Affiliation(s)
- Congjun Zhu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
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47
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Qu HJ, Yuan L, Jia CX, Yu HT, Xu H. DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals-Composition and Correlation Analysis of Kinetic Barriers. Molecules 2020; 25:molecules25194509. [PMID: 33019654 PMCID: PMC7582687 DOI: 10.3390/molecules25194509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 11/20/2022] Open
Abstract
Understanding the hydrogen atom abstraction (HAA) reactions of N-heterocyclic carbene (NHC)-boranes is essential for extending the practical applications of boron chemistry. In this study, density functional theory (DFT) computations were performed for the HAA reactions of a series of NHC-boranes attacked by •CH2CN, Me• and Et• radicals. Using the computed data, we investigated the correlations of the activation and free energy barriers with their components, including the intrinsic barrier, the thermal contribution of the thermodynamic reaction energy to the kinetic barriers, the activation Gibbs free energy correction and the activation zero-point vibrational energy correction. Furthermore, to describe the dependence of the activation and free energy barriers on the thermodynamic reaction energy or reaction Gibbs free energy, we used a three-variable linear model, which was demonstrated to be more precise than the two-variable Evans–Polanyi linear free energy model and more succinct than the three-variable Marcus-theory-based nonlinear HAA model. The present work provides not only a more thorough understanding of the compositions of the barriers to the HAA reactions of NHC-boranes and the HAA reactivities of the substrates but also fresh insights into the suitability of various models for describing the relationships between the kinetic and thermodynamic physical quantities.
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Affiliation(s)
- Hong-jie Qu
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China; (H.-j.Q.); (L.Y.); (C.-x.J.)
- College of Science, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Lang Yuan
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China; (H.-j.Q.); (L.Y.); (C.-x.J.)
| | - Cai-xin Jia
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China; (H.-j.Q.); (L.Y.); (C.-x.J.)
| | - Hai-tao Yu
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China; (H.-j.Q.); (L.Y.); (C.-x.J.)
- Correspondence: (H.-t.Y.); (H.X.); Tel.: +86-451-86608616 (H.-t.Y.)
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China; (H.-j.Q.); (L.Y.); (C.-x.J.)
- Correspondence: (H.-t.Y.); (H.X.); Tel.: +86-451-86608616 (H.-t.Y.)
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48
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Qi J, Zhang F, Jin J, Zhao Q, Li B, Liu L, Wang Y. New Radical Borylation Pathways for Organoboron Synthesis Enabled by Photoredox Catalysis. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915619] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Jing Qi
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
| | - Feng‐Lian Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
| | - Ji‐Kang Jin
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
| | - Qiang Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
| | - Bin Li
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
| | - Lin‐Xuan Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
| | - Yi‐Feng Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Hefei 230026 China
- Center for Excellence in Molecular Synthesis of CAS Hefei 230026 China
- State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 300071 China
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49
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Zhu C, Dong J, Liu X, Gao L, Zhao Y, Xie J, Li S, Zhu C. Photoredox‐Controlled β‐Regioselective Radical Hydroboration of Activated Alkenes with NHC‐Boranes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Congjun Zhu
- 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
| | - Jie Dong
- 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
| | - Xueting Liu
- Institute of Theoretical and Computational Chemistry School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Liuzhou Gao
- Institute of Theoretical and Computational Chemistry School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Yue Zhao
- 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
| | - Shuhua Li
- Institute of Theoretical and Computational Chemistry School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Chengjian Zhu
- 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
- State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Shanghai 200032 China
- College of Chemistry and Molecular Engineering Zhengzhou University Zhengzhou 450001 China
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50
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Vil' VA, Grishin SS, Baberkina EP, Kostyagina VA, Kovalenko AE, Terent'ev AO. Radical addition of tetrahydrofuran to imines assisted by tert-butyl hydroperoxide. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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