1
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Buzsaki SR, Mason SM, Kattamuri PV, Serviano JMI, Rodriguez DN, Wilson CV, Hood DM, Ellefsen JD, Lu YC, Kan J, West JG, Miller SJ, Holland PL. Fe/Thiol Cooperative Hydrogen Atom Transfer Olefin Hydrogenation: Mechanistic Insights That Inform Enantioselective Catalysis. J Am Chem Soc 2024. [PMID: 38875703 DOI: 10.1021/jacs.4c04047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2024]
Abstract
Asymmetric hydrogenation of activated olefins using transition metal catalysis is a powerful tool for the synthesis of complex molecules, but traditional metal catalysts have difficulty with enantioselective reduction of electron-neutral, electron-rich, and minimally functionalized olefins. Hydrogenation based on radical, metal-catalyzed hydrogen atom transfer (mHAT) mechanisms offers an outstanding opportunity to overcome these difficulties, enabling the mild reduction of these challenging olefins with selectivity that is complementary to traditional hydrogenations with H2. Further, mHAT presents an opportunity for asymmetric induction through cooperative hydrogen atom transfer (cHAT) using chiral thiols. Here, we report insights from a mechanistic study of an iron-catalyzed achiral cHAT reaction and leverage these insights to deliver stereocontrol from chiral thiols. Kinetic analysis and variation of silane structure point to the transfer of hydride from silane to iron as the likely rate-limiting step. The data indicate that the selectivity-determining step is quenching of the alkyl radical by thiol, which becomes a more potent H atom donor when coordinated to iron(II). The resulting iron(III)-thiolate complex is in equilibrium with other iron species, including FeII(acac)2, which is shown to be the predominant off-cycle species. The enantiodetermining nature of the thiol trapping step enables enantioselective net hydrogenation of olefins through cHAT using a commercially available glucose-derived thiol catalyst with up to 80:20 enantiomeric ratio. To the best of our knowledge, this is the first demonstration of asymmetric hydrogenation via iron-catalyzed mHAT. These findings advance our understanding of cooperative radical catalysis and act as a proof of principle for the development of enantioselective iron-catalyzed mHAT reactions.
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Affiliation(s)
- Sarah R Buzsaki
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
| | - Savannah M Mason
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | | | - Juan M I Serviano
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Dinora N Rodriguez
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
| | - Conner V Wilson
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Drew M Hood
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
| | - Jonathan D Ellefsen
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Yen-Chu Lu
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
| | - Jolie Kan
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
| | - Julian G West
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
| | - Scott J Miller
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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2
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Yamaguchi Y, Hirata Y, Higashida K, Yoshino T, Matsunaga S. Cobalt/Photoredox Dual-Catalyzed Cross-Radical Coupling of Alkenes via Hydrogen Atom Transfer and Homolytic Substitution. Org Lett 2024; 26:4893-4897. [PMID: 38836750 DOI: 10.1021/acs.orglett.4c01370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Cobalt-catalyzed metal hydride hydrogen atom transfer (MHAT) in combination with photoredox catalysis has emerged as a powerful synthetic method, owing to its redox nature and applicability to various radical precursors. Herein, we describe a cross-radical coupling reaction under cobalt/photoredox dual catalysis. MHAT and homolytic substitution (SH2) processes enabled Markovnikov-selective hydrobenzylation of di/trisubstituted alkenes, affording products with a quaternary carbon center in a redox-neutral manner.
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Affiliation(s)
- Yuto Yamaguchi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0808, Japan
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Hirata
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0808, Japan
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kosuke Higashida
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tatsuhiko Yoshino
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0808, Japan
| | - Shigeki Matsunaga
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0808, Japan
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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3
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Zhang J, Huan XD, Wang X, Li GQ, Xiao WJ, Chen JR. Recent advances in C(sp 3)-N bond formation via metallaphoto-redox catalysis. Chem Commun (Camb) 2024. [PMID: 38832416 DOI: 10.1039/d4cc01969e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The C(sp3)-N bond is ubiquitous in natural products, pharmaceuticals, biologically active molecules and functional materials. Consequently, the development of practical and efficient methods for C(sp3)-N bond formation has attracted more and more attention. Compared to the conventional ionic pathway-based thermal methods, photochemical processes that proceed through radical mechanisms by merging photoredox and transition-metal catalyses have emerged as powerful and alternative tools for C(sp3)-N bond formation. In this review, recent advances in the burgeoning field of C(sp3)-N bond formation via metallaphotoredox catalysis have been highlighted. The contents of this review are categorized according to the transition metals used (copper, nickel, cobalt, palladium, and iron) together with photocatalysis. Emphasis is placed on methodology achievements and mechanistic insight, aiming to inspire chemists to invent more efficient radical-involved C(sp3)-N bond-forming reactions.
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Affiliation(s)
- Juan Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Xiao-Die Huan
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
| | - Xin Wang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Guo-Qing Li
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
| | - Wen-Jing Xiao
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
| | - Jia-Rong Chen
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
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4
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Lindner H, Amberg WM, Martini T, Fischer DM, Moore E, Carreira EM. Photo- and Cobalt-Catalyzed Synthesis of Heterocycles via Cycloisomerization of Unactivated Olefins. Angew Chem Int Ed Engl 2024; 63:e202319515. [PMID: 38415968 DOI: 10.1002/anie.202319515] [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: 12/18/2023] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 02/29/2024]
Abstract
We report a general, intramolecular cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and tolerates ethers, esters, protected amines, acetals, pyrazoles, carbamates, and arenes. It is amenable to N-, O-, as well as C-nucleophiles, yielding a number of different heterocycles including, but not limited to, pyrrolidines, piperidines, oxazolidinones, and lactones. Use of both a benzothiazinoquinoxaline as organophotocatalyst and a Co-salen catalyst obviates the need for stoichiometric oxidant or reductant. We showcase the utility of the protocol in late-stage drug diversification and synthesis of several small natural products.
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Affiliation(s)
- Henry Lindner
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Willi M Amberg
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Tristano Martini
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - David M Fischer
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Eléonore Moore
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Erick M Carreira
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
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5
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Xu S, Mi R, Zheng G, Li X. Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides via C-H activation and formal phosphoryl migration. Chem Sci 2024; 15:6012-6021. [PMID: 38665527 PMCID: PMC11040647 DOI: 10.1039/d4sc00649f] [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: 01/28/2024] [Accepted: 03/11/2024] [Indexed: 04/28/2024] Open
Abstract
A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized via cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields via the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity. Photophysical properties of selected 1,2-dihydrophosphete oxides are also disclosed.
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Affiliation(s)
- Shengbo Xu
- School of Chemistry and Chemical Engineering, Shaanxi Normal University (SNNU) Xi'an 710062 P. R. China
| | - Ruijie Mi
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Sciences, Shandong University Qingdao 266237 P. R. China
| | - Guangfan Zheng
- Department of Chemistry, Northeast Normal University Changchun 130024 P. R. China
| | - Xingwei Li
- School of Chemistry and Chemical Engineering, Shaanxi Normal University (SNNU) Xi'an 710062 P. R. China
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Sciences, Shandong University Qingdao 266237 P. R. China
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6
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Shibutani S, Nagao K, Ohmiya H. A Dual Cobalt and Photoredox Catalysis for Hydrohalogenation of Alkenes. J Am Chem Soc 2024; 146:4375-4379. [PMID: 38300804 DOI: 10.1021/jacs.3c10133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
We demonstrate hydrohalogenation of aliphatic alkenes with collidine·HX salts through dual photoredox/cobalt catalysis. The dual catalysis enables conversion of a proton and a halide anion from collidine·HX salt to a nucleophilic hydrogen radical equivalent and an electrophilic halogen radical equivalent and delivery of them to an alkene moiety. This protocol allows for introduction of fluorine, chlorine, bromine, or iodine atom to alkene, producing highly functionalized alkyl halides.
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Affiliation(s)
- Shotaro Shibutani
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kazunori Nagao
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Hirohisa Ohmiya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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7
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Wilson CV, Holland PL. Mechanism of Alkene Hydrofunctionalization by Oxidative Cobalt(salen) Catalyzed Hydrogen Atom Transfer. J Am Chem Soc 2024; 146:2685-2700. [PMID: 38227206 PMCID: PMC10872242 DOI: 10.1021/jacs.3c12329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Oxidative MHAT hydrofunctionalization of alkenes provides a mild cobalt-catalyzed route to forming C-N and C-O bonds. Here, we characterize relevant salen-supported cobalt complexes and their reactions with alkenes, silanes, oxidant, and solvent. These stoichiometric investigations are complemented by kinetic studies of the catalytic reaction and catalyst speciation. We describe the solution characterization of an elusive cobalt(III) fluoride complex, which surprisingly is not the species that reacts with silane under catalytic conditions; rather, a cobalt(III) aquo complex is more active. Accordingly, the addition of water (0.15 M) speeds the catalytic reaction, and kinetic studies show that water addition enables catalytic product formation in 2 h at -50 °C in acetone. Under these conditions, cobalt(III) resting states can be observed by UV-vis spectrophotometry, including a cobalt(III)-alkyl complex. It comes from a transient cobalt(III) hydride complex that is formed in the turnover-limiting step of the catalytic cycle. This hydride readily degrades but not to H2; it releases H+ through a bimetallic pathway that explains the [Co]2 dependence of the off-cycle reaction. In contrast, the rate of the catalytic reaction follows the power law kobs[Co]1[silane]1. Because of the different [Co] dependence of the catalytic reaction and the degradation reaction, lower catalyst loading improves the yield of the catalytic reaction by reducing the relative rate of unproductive silane/oxidant consumption. These studies illuminate mechanistic details of oxidative MHAT hydrofunctionalization of alkenes and lay the groundwork for understanding other catalytic reactions mediated by cobalt hydride and cobalt alkyl complexes.
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Affiliation(s)
- Conner V. Wilson
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520, USA
| | - Patrick L. Holland
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520, USA
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8
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Cai J, Zeng G, Jiang K, Luo H, Yin B. Intramolecular Cobalt/Visible Light Cocatalyzed Reductive Coupling of Unactivated Arenes with Unactivated Alkenes. Org Lett 2024; 26:327-331. [PMID: 38160449 DOI: 10.1021/acs.orglett.3c03978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
A protocol for the intramolecular reductive coupling of unactivated arenes with unactivated alkenes has been developed with the aid of a cooperative visible light/cobalt catalytic system. This coupling is achieved via radical cascade cyclization using amines as terminal reducing reagents and water as the main hydrogen source. In their form, readily available N-allyl benzamides are converted to the corresponding spiro cyclohexadiene-lactam or β-phenethylamine analogues in moderate to excellent yields.
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Affiliation(s)
- Jianpeng Cai
- School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan, Tianhe, Guangzhou 510640, China
- Guangzhou Addenda Chemical Corp. Ltd, 31 Kefeng, Huangpu, Guangzhou,510663, China
| | - Guohui Zeng
- School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan, Tianhe, Guangzhou 510640, China
- Guangzhou Addenda Chemical Corp. Ltd, 31 Kefeng, Huangpu, Guangzhou,510663, China
| | - Kai Jiang
- School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan, Tianhe, Guangzhou 510640, China
- Guangzhou Addenda Chemical Corp. Ltd, 31 Kefeng, Huangpu, Guangzhou,510663, China
| | - Hui Luo
- School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan, Tianhe, Guangzhou 510640, China
- Guangzhou Addenda Chemical Corp. Ltd, 31 Kefeng, Huangpu, Guangzhou,510663, China
| | - Biaolin Yin
- School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan, Tianhe, Guangzhou 510640, China
- Guangzhou Addenda Chemical Corp. Ltd, 31 Kefeng, Huangpu, Guangzhou,510663, China
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9
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Mayerhofer VJ, Lippolis M, Teskey CJ. Dual-Catalysed Intermolecular Reductive Coupling of Dienes and Ketones. Angew Chem Int Ed Engl 2024; 63:e202314870. [PMID: 37947372 DOI: 10.1002/anie.202314870] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/12/2023]
Abstract
We report a mild, catalytic method for the intermolecular reductive coupling of feedstock dienes and styrenes with ketones. Our conditions allow concomitant formation of a cobalt hydride species and single-electron reduction of ketones. Subsequent selective hydrogen-atom transfer from the cobalt hydride generates an allylic radical which can selectively couple with the persistent radical-anion of the ketone. This radical-radical coupling negates unfavourable steric interactions of ionic pathways and avoids the unstable alkoxy radical of previous radical olefin-carbonyl couplings, which were limited, as a result, to aldehydes. Applications of this novel and straightforward approach include the efficient synthesis of drug molecules, key intermediates in drug synthesis and site-selective late-stage functionalisation.
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Affiliation(s)
- Victor J Mayerhofer
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Martina Lippolis
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Christopher J Teskey
- Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
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10
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Yan H, Shan JR, Zhang F, Chen Y, Zhang X, Liao Q, Hao E, Shi L. Radical Crotylation of Aldehydes with 1,3-Butadiene by Photoredox Cobalt and Titanium Dual Catalysis. Org Lett 2023; 25:7694-7699. [PMID: 37842952 DOI: 10.1021/acs.orglett.3c03003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Metal-hydride hydrogen atom transfer (MHAT) has been recognized as a powerful method for alkene functionalization; however, photochemical MAT-mediated chemoselective functionalization of dienes remains undeveloped. In this study, we report a radical strategy (1e-) through MHAT using photoredox cobalt and titanium dual catalysis for aldehyde crotylation with butadiene, achieving excellent regio- and diastereoselectivity.
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Affiliation(s)
- Huaipu Yan
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Jing-Ran Shan
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Fengzhi Zhang
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Yuqing Chen
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Xinyi Zhang
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Qian Liao
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Erjun Hao
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Lei Shi
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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11
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Mu QQ, Guo AX, Cai X, Qin YY, Liu XL, Ye FZ, Yang HJ, Xiao X, Liu XW. Cobalt's Dual Role in Promoting C3-Glycosylation of Indoles: Unraveling Mechanistic Insights. Org Lett 2023; 25:7040-7045. [PMID: 37721454 DOI: 10.1021/acs.orglett.3c02624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
In this study, we present a cobalt-catalyzed C3-glycosylation of indoles using unfunctionalized glycals, yielding 3-indolyl-C-deoxyglycosides. These compounds hold promise as sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors for treating type 2 diabetes. Control experiments unveiled that cobalt assumes a dual role, facilitating catalytic C-glycosylation while unexpectedly driving the anomerization of α-anomers through endocyclic cleavage of the C1-O5 bond, resulting in the formation of β-C-deoxyglycosides. Furthermore, density functional theory (DFT) calculations shed light on the reaction mechanism, emphasizing the significant role of the pyridine group of indole in stabilizing transition states and intermediates.
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Affiliation(s)
- Qiu-Qi Mu
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Ao-Xin Guo
- School of Chemistry, Chemical Engineering and Biotechnology Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Xin Cai
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Yang-Yang Qin
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Xing-Le Liu
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Fang-Zhen Ye
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Hui-Jie Yang
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Xiong Xiao
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China
| | - Xue-Wei Liu
- School of Chemistry, Chemical Engineering and Biotechnology Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
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12
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Durin G, Lee MY, Pogany MA, Weyhermüller T, Kaeffer N, Leitner W. Hydride-Free Hydrogenation: Unraveling the Mechanism of Electrocatalytic Alkyne Semihydrogenation by Nickel-Bipyridine Complexes. J Am Chem Soc 2023; 145:17103-17111. [PMID: 37490541 PMCID: PMC10416305 DOI: 10.1021/jacs.3c03340] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Indexed: 07/27/2023]
Abstract
Hydrogenation reactions of carbon-carbon unsaturated bonds are central in synthetic chemistry. Efficient catalysis of these reactions classically recourses to heterogeneous or homogeneous transition-metal species. Whether thermal or electrochemical, C-C multiple bond catalytic hydrogenations commonly involve metal hydrides as key intermediates. Here, we report that the electrocatalytic alkyne semihydrogenation by molecular Ni bipyridine complexes proceeds without the mediation of a hydride intermediate. Through a combined experimental and theoretical investigation, we disclose a mechanism that primarily involves a nickelacyclopropene resting state upon alkyne binding to a low-valent Ni(0) species. A following sequence of protonation and electron transfer steps via Ni(II) and Ni(I) vinyl intermediates then leads to olefin release in an overall ECEC-type pattern as the most favored pathway. Our results also evidence that pathways involving hydride intermediates are strongly disfavored, which in turn promotes high semihydrogenation selectivity by avoiding competing hydrogen evolution. While bypassing catalytically competent hydrides, this type of mechanism still retains inner-metal-sphere characteristics with the formation of organometallic intermediates, often essential to control regio- or stereoselectivity. We think that this approach to electrocatalytic reductions of unsaturated organic groups can open new paradigms for hydrogenation or hydroelementation reactions.
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Affiliation(s)
- Gabriel Durin
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Mi-Young Lee
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Martina A. Pogany
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Nicolas Kaeffer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Walter Leitner
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
- Institut
für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
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