1
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Jones BT, Maulide N. Lewis Acid-Driven Inverse Hydride Shuttle Catalysis. Angew Chem Int Ed Engl 2024; 63:e202320001. [PMID: 38551113 DOI: 10.1002/anie.202320001] [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: 12/25/2023] [Indexed: 05/30/2024]
Abstract
Inverse hydride shuttle catalysis provides a multicomponent platform for the highly efficient synthesis of alkaloid frameworks with exquisite diastereoselectivity. However, a number of limitations hinder this method, primarily the strict requirement for highly electron-deficient acceptors. Herein, we present a general Lewis acid-driven approach to address this constraint, and have developed two broad strategies enabling the modular synthesis of complex azabicycles that were entirely unattainable using the previous method. The enhanced synthetic flexibility facilitates a streamlined asymmetric cyclization, leading to a concise total synthesis of the alkaloid (-)-tashiromine.
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Affiliation(s)
- Benjamin T Jones
- Faculty of Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, 1090, Vienna, Austria
| | - Nuno Maulide
- Faculty of Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, 1090, Vienna, Austria
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2
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Alvarez-Montoya A, Gillions JP, Winfrey L, Hawker RR, Singh K, Ortu F, Fu Y, Li Y, Pulis AP. B(C 6F 5) 3-Catalyzed Dehydrogenation of Pyrrolidines to Form Pyrroles. ACS Catal 2024; 14:4856-4864. [PMID: 38601781 PMCID: PMC11002826 DOI: 10.1021/acscatal.3c05444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 04/12/2024]
Abstract
Pyrroles are important N-heterocycles found in medicines and materials. The formation of pyrroles from widely accessible pyrrolidines is a potentially attractive strategy but is an underdeveloped approach due to the sensitivity of pyrroles to the oxidative conditions required to achieve such a transformation. Herein, we report a catalytic approach that employs commercially available B(C6F5)3 in an operationally simple procedure that allows pyrrolidines to serve as direct synthons for pyrroles. Mechanistic studies have revealed insights into borane-catalyzed dehydrogenative processes.
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Affiliation(s)
| | | | - Laura Winfrey
- School
of Chemistry, University of Leicester, Leicester LE1 7RH, U.K.
| | - Rebecca R. Hawker
- School
of Chemistry, University of Leicester, Leicester LE1 7RH, U.K.
| | - Kuldip Singh
- School
of Chemistry, University of Leicester, Leicester LE1 7RH, U.K.
| | - Fabrizio Ortu
- School
of Chemistry, University of Leicester, Leicester LE1 7RH, U.K.
| | - Yukang Fu
- School
of Chemical Engineering, Dalian University
of Technology, No. 2 Linggong Road, Dalian 116024, P. R. China
| | - Yang Li
- School
of Chemical Engineering, Dalian University
of Technology, No. 2 Linggong Road, Dalian 116024, P. R. China
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3
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Elsherbeni S, Melen RL, Pulis AP, Morrill LC. Accessing Highly Substituted Indoles via B(C 6F 5) 3-Catalyzed Secondary Alkyl Group Transfer. J Org Chem 2024; 89:4244-4248. [PMID: 38389441 PMCID: PMC10949240 DOI: 10.1021/acs.joc.4c00025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024]
Abstract
Herein, we report a synthetic method to access a range of highly substituted indoles via the B(C6F5)3-catalyzed transfer of 2° alkyl groups from amines. The transition-metal-free catalytic approach has been demonstrated across a broad range of indoles and amine 2° alkyl donors, including various substituents on both reacting components, to access useful C(3)-alkylated indole products. The alkyl transfer process can be performed using Schlenk line techniques in combination with commercially available B(C6F5)3·nH2O and solvents, which obviates the requirement for specialized equipment (e.g., glovebox).
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Affiliation(s)
- Salma
A. Elsherbeni
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, U.K.
- Department
of Pharmaceutical Chemistry, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Rebecca L. Melen
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff, CF24 4HQ, U.K.
| | | | - Louis C. Morrill
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, U.K.
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4
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Zhang R, Ma R, Chen R, Wang L, Ma Y. Regioselective C 3Alkylation of Indoles for the Synthesis of Bis(indolyl)methanes and 3-Styryl Indoles. J Org Chem 2024; 89:1846-1857. [PMID: 38214898 DOI: 10.1021/acs.joc.3c02551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Herein, we describe an efficient transition-metal-free regioselective C3alkylation of indoles for the synthesis of bis(indolyl)methanes and 3-styryl indoles. Nitrobenzene is employed as the oxidant to oxidize the alcohols in the presence of a strong base and the reaction avoids the use of transition metals such as Ru and Mn. The protocol provides a favorable route to access biologically active compounds such as arundine, vibrindole A, and turbomycin B.
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Affiliation(s)
- Ruiqin Zhang
- Institute of Advanced Studies and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang 318000, P. R. China
- School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou 310053, P. R. China
| | - Renchao Ma
- Institute of Advanced Studies and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang 318000, P. R. China
| | - Rener Chen
- Institute of Advanced Studies and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang 318000, P. R. China
| | - Lei Wang
- Institute of Advanced Studies and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang 318000, P. R. China
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, P. R. China
| | - Yongmin Ma
- Institute of Advanced Studies and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang 318000, P. R. China
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5
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Zhang M, Tang ZL, Luo H, Wang XC. β-C-H Allylation of Trialkylamines with Allenes Promoted by Synergistic Borane/Palladium Catalysis. Angew Chem Int Ed Engl 2023:e202317610. [PMID: 38095883 DOI: 10.1002/anie.202317610] [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: 11/19/2023] [Indexed: 12/29/2023]
Abstract
Functionalization of the C(sp3 )-H bonds of trialkylamines is challenging, especially for reactions at positions other than the α position. Herein, we report a method for β-C(sp3 )-H allylation of trialkylamines. In these reactions, which involve synergistic borane/palladium catalysis, an enamine intermediate is first generated from the amine via α,β-dehydrogenation promoted by B(C6 F5 )3 and a base, and then the enamine undergoes palladium-catalyzed reaction with an allene to give the allylation product. Because the hydride and the proton resulting from the initial dehydrogenation are ultimately shuttled to the product by B(C6 F5 )3 and the palladium catalyst, respectively, these reactions show excellent atom economy. The establishment of this method paves the way for future studies of C-H functionalization of trialkylamines by means of synergistic borane/transition-metal catalysis.
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Affiliation(s)
- Ming Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Zi-Lu Tang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Heng Luo
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiao-Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
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6
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Pazur EJ, Tasker NR, Wipf P. C3-Functionalization of indoles with α-heteroaryl-substituted methyl alcohols. Org Biomol Chem 2023; 21:8651-8657. [PMID: 37873703 DOI: 10.1039/d3ob01432k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The transition metal-free Cs2CO3/Oxone®-mediated C3-alkylation of indoles proceeds in moderate to high yields with a variety of C4-C7 functionalized indoles and is applicable to 2-, 3- and 4-hydroxymethyl pyridines and related electron-deficient heterocycles, permitting novel late-stage drug functionalizations. Preliminary mechanistic studies support a hydrogen autotransfer-type chain process starting with an initial oxidation of the alcohol to the corresponding aldehyde, followed by a subsequent condensation onto indole and reduction/hydride delivery from another equivalent of the primary alcohol.
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Affiliation(s)
- Ethan J Pazur
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Nikhil R Tasker
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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7
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Xu X, Gao D, Wang J, Tang XY, Wang L. The B(C 6F 5) 3·H 2O promoted synthesis of fluoroalkylated 3,3',3''-trisindolylmethanes from fluorocarboxylic acids and indoles. Org Biomol Chem 2023; 21:1478-1486. [PMID: 36655817 DOI: 10.1039/d2ob02241a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Trisindolylmethanes (TIMs) exist in many bioactive natural products and are frequently applied in medicinal chemistry and materials science. Herein, a simple and efficient protocol promoted by B(C6F5)3·H2O for the synthesis of their fluoroalkylated analogues, fluoroalkylated 3,3',3''-TIMs, is reported for the first time. Easily accessible fluorocarboxylic acids are utilized as the fluoroalkyl sources, exhibiting an obvious fluorine effect. This convenient and green process features mild and metal-free conditions, easy scale-up, and an environmentally friendly byproduct.
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Affiliation(s)
- Xin Xu
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Bio-inorganic Chemistry & Materia Medica; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Dandan Gao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Bio-inorganic Chemistry & Materia Medica; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Jiahua Wang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Bio-inorganic Chemistry & Materia Medica; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Xiang-Ying Tang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Bio-inorganic Chemistry & Materia Medica; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Long Wang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education; Hubei Key Laboratory of Bio-inorganic Chemistry & Materia Medica; School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
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8
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Greiner LC, Arichi N, Inuki S, Ohno H. Gold(I)-Catalyzed Benzylic C(sp 3 )-H Functionalizations: Divergent Synthesis of Indole[a]- and [b]-Fused Polycycles. Angew Chem Int Ed Engl 2023; 62:e202213653. [PMID: 36255174 DOI: 10.1002/anie.202213653] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/17/2022] [Accepted: 10/17/2022] [Indexed: 11/05/2022]
Abstract
Phenyl azides substituted by an (alkylphenyl)ethynyl group facilitate benzylic sp3 (C-H) functionalization in the presence of a JohnPhosAu catalyst, resulting in indole-fused tetra- and pentacycles via divergent N- or C-cyclization. The chemoselectivity is influenced depending on the counter-anion, the electron density of the α-imino gold(I) carbene, and the alkyl groups stabilizing the benzylic carbocation originating from a 1,5-hydride shift. An isotopic labeling experiment demonstrates the involvement of an indolylgold(I) species resulting from a tautomerization that is much faster than the deauration. The formation of a benzylic sp3 (C-H) functionalization leading to an indole-fused seven-membered ring is also demonstrated.
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Affiliation(s)
- Luca C Greiner
- Graduate School of Pharmaceutical Sciences, Kyoto University Sakyo-ku, Kyoto, 606-8501, Japan
| | - Norihito Arichi
- Graduate School of Pharmaceutical Sciences, Kyoto University Sakyo-ku, Kyoto, 606-8501, Japan
| | - Shinsuke Inuki
- Graduate School of Pharmaceutical Sciences, Kyoto University Sakyo-ku, Kyoto, 606-8501, Japan
| | - Hiroaki Ohno
- Graduate School of Pharmaceutical Sciences, Kyoto University Sakyo-ku, Kyoto, 606-8501, Japan
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9
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Kustiana BA, Melen RL, Morrill LC. One-Pot Synthesis of Styrene Derivatives from Allyl Silanes via B(C 6F 5) 3-Catalyzed Isomerization–Hiyama Coupling. Org Lett 2022; 24:8694-8697. [DOI: 10.1021/acs.orglett.2c03584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Betty A. Kustiana
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Rebecca L. Melen
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Louis C. Morrill
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
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10
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Kustiana BA, Elsherbeni SA, Linford‐Wood TG, Melen RL, Grayson MN, Morrill LC. B(C 6 F 5 ) 3 -Catalyzed E-Selective Isomerization of Alkenes. Chemistry 2022; 28:e202202454. [PMID: 35943082 PMCID: PMC9804281 DOI: 10.1002/chem.202202454] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Indexed: 01/05/2023]
Abstract
Herein, we report the B(C6 F5 )3 -catalyzed E-selective isomerization of alkenes. The transition-metal-free method is applicable across a diverse array of readily accessible substrates, giving access to a broad range of synthetically useful products containing versatile stereodefined internal alkenes. The reaction mechanism was investigated by using synthetic and computational methods.
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Affiliation(s)
- Betty A. Kustiana
- Cardiff Catalysis InstituteSchool of ChemistryCardiff University Main BuildingPark PlaceCardiffCF10 3ATUK
| | - Salma A. Elsherbeni
- Cardiff Catalysis InstituteSchool of ChemistryCardiff University Main BuildingPark PlaceCardiffCF10 3ATUK
| | | | - Rebecca L. Melen
- Cardiff Catalysis InstituteSchool of ChemistryCardiff University Main BuildingPark PlaceCardiffCF10 3ATUK
| | | | - Louis C. Morrill
- Cardiff Catalysis InstituteSchool of ChemistryCardiff University Main BuildingPark PlaceCardiffCF10 3ATUK
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11
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Phatake RS, Averdunk A, Würtele C, Gellrich U. Piers’ Borane-Catalyzed Dimerization of Arylallenes via Transborylation: A Synthetic and Mechanistic Study. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ravindra S. Phatake
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Christian Würtele
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
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12
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He Y, Liu Q, Du Z, Xu Y, Cao L, Zhang X, Fan X. B(C 6F 5) 3-Catalyzed α,β-Difunctionalization and C-N Bond Cleavage of Saturated Amines with Benzo[ c]isoxazoles: Access to Quinoline Derivatives. J Org Chem 2022; 87:14840-14845. [PMID: 36269623 DOI: 10.1021/acs.joc.2c01290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, we disclose a strategy to realize α,β-difunctionalization and C-N bond cleavage of saturated amines with benzo[c]isoxazoles via a B(C6F5)3-catalyzed consecutive hydrogen-borrowing and [4 + 2] cycloaddition followed by a C-N bond cleavage process. In general, the reactions proceed efficiently in the absence of any oxidant and metal catalyst to afford a broad range of quinoline derivatives starting from easily accessible substrates in an atom-economical manner.
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Affiliation(s)
- Yan He
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Qimeng Liu
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Zihe Du
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yanhua Xu
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Lingyu Cao
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xinying Zhang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xuesen Fan
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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13
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Tian J, Sun W, Li R, Tian G, Wang X. Borane/Gold(I)‐Catalyzed C−H Functionalization Reactions and Cycloaddition Reactions of Amines and α‐Alkynylenones. Angew Chem Int Ed Engl 2022; 61:e202208427. [DOI: 10.1002/anie.202208427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Indexed: 01/03/2023]
Affiliation(s)
- Jun‐Jie Tian
- State Key Laboratory and Institute of Elemento-Organic Chemistry Haihe Laboratory of Sustainable Chemical Transformations Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Wei Sun
- State Key Laboratory and Institute of Elemento-Organic Chemistry Haihe Laboratory of Sustainable Chemical Transformations Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Rui‐Rui Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry Haihe Laboratory of Sustainable Chemical Transformations Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Gui‐Xiu Tian
- State Key Laboratory and Institute of Elemento-Organic Chemistry Haihe Laboratory of Sustainable Chemical Transformations Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Xiao‐Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry Haihe Laboratory of Sustainable Chemical Transformations Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
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14
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Liang XS, Li RD, Sun W, Liu Z, Wang XC. Coupling of 2 H-Chromenes with Silyl Ketene Acetals Enabled by Borane Catalysis. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xin-Shen Liang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Rui-Dong Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Wei Sun
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Zhong Liu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Xiao-Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
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15
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Tian JJ, Sun W, Li RR, Tian GX, Wang XC. Borane/Gold(I)‐Catalyzed C–H Functionalization Reactions and Cycloaddition Reactions of Amines and α‐Alkynylenones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202208427] [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)
| | - Wei Sun
- Nankai University College of Chemistry CHINA
| | - Rui-Rui Li
- Nankai University College of Chemistry CHINA
| | | | - Xiao-Chen Wang
- Nankai University College of Chemistry 94 Weijin Rd 300071 Tianjin CHINA
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16
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Golla S, Jalagam S, Poshala S, Kokatla HP. Transition metal-free functionalization of 2-oxindoles via sequential aldol and reductive aldol reactions using rongalite as a C1 reagent. Org Biomol Chem 2022; 20:4926-4932. [PMID: 35506377 DOI: 10.1039/d2ob00665k] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A sequential one-pot classical aldol, transition-metal and hydride-free reductive aldol reaction is reported here for C(sp3)- H functionalization of 2-oxindoles using the multifaceted reagent rongalite. Here, rongalite functions as a hydride-free reducing agent and double C1 unit donor. This protocol enables the synthesis of a wide range of 3-methylindoline-2-ones and 3-(hydroxymethyl)-3-methylindolin-2-ones from 2-oxindoles (65-95% yields), which are the synthetic precursors for many natural products. Some of the important aspects of this synthetic approach include one-pot methylation and hydroxymethylation, low-cost rongalite (ca. $0.03 per 1 g), mild reaction conditions and applicability to gram-scale synthesis.
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Affiliation(s)
- Sivaparwathi Golla
- Department of Chemistry, National Institute of Technology Warangal, Warangal, Telangana-506004, India.
| | - Swathi Jalagam
- Department of Chemistry, National Institute of Technology Warangal, Warangal, Telangana-506004, India.
| | - Soumya Poshala
- Department of Chemistry, National Institute of Technology Warangal, Warangal, Telangana-506004, India.
| | - Hari Prasad Kokatla
- Department of Chemistry, National Institute of Technology Warangal, Warangal, Telangana-506004, India.
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17
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Xiao Y, Tang L, Xu TT, Feng JJ. Boron Lewis Acid Catalyzed Intermolecular trans-Hydroarylation of Ynamides with Hydroxyarenes. Org Lett 2022; 24:2619-2624. [PMID: 35389667 DOI: 10.1021/acs.orglett.2c00574] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An atom-economic protocol for the efficient and highly chemo- and stereoselective trans-hydroarylation of ynamides with hydroxyarenes catalyzed by B(C6F5)3 has been developed. Use of readily available starting materials, low catalyst loading, mild reaction conditions, a broad substrate scope, ease of scale-up, and versatile functionalizations of the enamide products make this approach very practical and attractive.
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Affiliation(s)
- Yuanjiu Xiao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Lei Tang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Tong-Tong Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Jian-Jun Feng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China
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18
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Paradies J, Köring L, Sitte NA. Towards the Development of Frustrated Lewis Pair (FLP) Catalyzed Hydrogenations of Tertiary and Secondary Carboxylic Amides. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1681-3972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractThe development of the frustrated Lewis pair catalyzed hydrogenation of tertiary and secondary amides is reviewed. Detailed insight into our strategies in order to overcome challenges during the reaction development process is provided. Furthermore, the developed chemistry is extended to the hydrogenation of polyamides and of trifluoroacetamides for the convenient introduction of trifluoroethyl groups into organic molecules.
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19
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Song H, Zhou H, Shen Y, Wang H, Song H, Cai X, Xu C. HFIP as Protonation Reagent and Solvent for Regioselective Alkylation of Indoles with All-Carbon Centers. J Org Chem 2022; 87:1086-1097. [PMID: 35015536 DOI: 10.1021/acs.joc.1c02412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The regio- and chemoselective construction of indole bearing an all-carbon center at the C3-position, a versatile bioactive building block, by C(sp2)-C(sp3) formation with olefins has been achieved through utilization of hexafluoroisopropanol (HFIP) as the protonation reagent and solvent. The catalytic reactions are operationally simple and green compared with previous reports utilizing elaborated olefins and catalysts. This protocol allows for alkylation of a variety of substituted indoles with diverse of styrene type alkenes in excellent yields and with high selectivity. Application of this protocol to the synthesis of drug was pursued and with an improved yield in contrast to previous art. Catalytic kinetics and deuterium-labeling experiments suggest that the rate-determining step involves the protonation of olefin by HFIP to generate carbocation, followed by electrophilic addition to indole derivative.
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Affiliation(s)
- Heng Song
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
| | - Hu Zhou
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
| | - Yang Shen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
| | - Hao Wang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
| | - Hua Song
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
| | - Xingwei Cai
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
| | - Chen Xu
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, P.R. China
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20
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. D, Sharma YB, Pant S, Dhaked DK, Guru MM. Borane-Catalyzed Dehydrogenative C‒C Bond Formation of Indoles with N-Tosylhydrazones: An Experimental and Computational Study. Org Chem Front 2022. [DOI: 10.1039/d2qo00552b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel dehydrogenative C‒C bond formation of indoles and N-tosylhydrazones to di(indolyl)methanes (DIMs) has been demonstrated using tris(pentafluorophenyl)borane as catalyst. A wide range of functional groups can be tolerated under...
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21
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Zhang BB, Peng S, Wang F, Lu C, Nie J, Chen Z, Yang G, Ma C. Borane-catalyzed cascade Friedel–Crafts alkylation/[1,5]-hydride transfer/Mannich cyclization to afford tetrahydroquinolines. Chem Sci 2022; 13:775-780. [PMID: 35173942 PMCID: PMC8768868 DOI: 10.1039/d1sc05629h] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/20/2021] [Indexed: 12/15/2022] Open
Abstract
We report a redox-neutral annulation reaction of tertiary amines with electron-deficient alkynes under metal-free and oxidant-free conditions.
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Affiliation(s)
- Bei-Bei Zhang
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Shuo Peng
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Feiyi Wang
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Cuifen Lu
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Junqi Nie
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Zuxing Chen
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Guichun Yang
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
| | - Chao Ma
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, P. R. China
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22
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Wasa M, Yesilcimen A. Enantioselective Cooperative Catalysis within Frustrated Lewis Pair Complexes. J SYN ORG CHEM JPN 2021. [DOI: 10.5059/yukigoseikyokaishi.79.1065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Masayuki Wasa
- Department of Chemistry, Merkert Chemistry Center, Boston College
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23
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Wu M, Wang S, Wang Y, Gao H, Yi W, Zhou Z. TFA‐Prompted/Rh(III)‐Catalysed Chemoselective C
3
− or C
2
−H Functionalization of Indoles with Methylenecyclopropanes. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Min Wu
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease School of Pharmaceutical Sciences & the Fifth Affiliated Hospital Guangzhou Medical University Guangzhou Guangdong 511436 P. R. China
| | - Shengdong Wang
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease School of Pharmaceutical Sciences & the Fifth Affiliated Hospital Guangzhou Medical University Guangzhou Guangdong 511436 P. R. China
| | - Yi Wang
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease School of Pharmaceutical Sciences & the Fifth Affiliated Hospital Guangzhou Medical University Guangzhou Guangdong 511436 P. R. China
| | - Hui Gao
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease School of Pharmaceutical Sciences & the Fifth Affiliated Hospital Guangzhou Medical University Guangzhou Guangdong 511436 P. R. China
| | - Wei Yi
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease School of Pharmaceutical Sciences & the Fifth Affiliated Hospital Guangzhou Medical University Guangzhou Guangdong 511436 P. R. China
| | - Zhi Zhou
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease School of Pharmaceutical Sciences & the Fifth Affiliated Hospital Guangzhou Medical University Guangzhou Guangdong 511436 P. R. China
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24
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Yang G, Pan J, Ke Y, Liu Y, Zhao Y. Tandem Catalytic Indolization/Enantioconvergent Substitution of Alcohols by Borrowing Hydrogen to Access Tricyclic Indoles. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Guoqiang Yang
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
| | - Jiaoting Pan
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
- Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 China
| | - Ya‐Ming Ke
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
| | - Yongbing Liu
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
| | - Yu Zhao
- Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
- Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 China
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25
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Zhang M, Wang XC. Bifunctional Borane Catalysis of a Hydride Transfer/Enantioselective [2+2] Cycloaddition Cascade. Angew Chem Int Ed Engl 2021; 60:17185-17190. [PMID: 34037295 DOI: 10.1002/anie.202106168] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Indexed: 02/04/2023]
Abstract
Herein, we present a mild and efficient method for synthesizing enantioenriched tetrahydroquinoline-fused cyclobutenes through a cascade reaction between 1,2-dihydroquinolines and alkynones with catalysis by chiral spiro-bicyclic bisboranes. The bisboranes served two functions: first they catalyzed a hydride transfer to convert the 1,2-dihydroquinoline substrate to a 1,4-dihydroquinoline, and then they activated the alkynone substrate for an enantioselective [2+2] cycloaddition reaction with the 1,4-dihydroquinoline generated in situ.
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Affiliation(s)
- Ming Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiao-Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
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26
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Zhou J, Huang J, Lu C, Jiang H, Huang L. B(C
6
F
5
)
3
‐Catalyzed Hydroarylation of Terminal Alkynes with Phenols. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100590] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jiaming Zhou
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp & Paper Engineering South China University of Technology Guangzhou 510640, People's Republic of China
| | - Jin Huang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp & Paper Engineering South China University of Technology Guangzhou 510640, People's Republic of China
| | - Changhui Lu
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp & Paper Engineering South China University of Technology Guangzhou 510640, People's Republic of China
| | - Huanfeng Jiang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp & Paper Engineering South China University of Technology Guangzhou 510640, People's Republic of China
| | - Liangbin Huang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp & Paper Engineering South China University of Technology Guangzhou 510640, People's Republic of China
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27
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Yang G, Pan J, Ke YM, Liu Y, Zhao Y. Tandem Catalytic Indolization/Enantioconvergent Substitution of Alcohols by Borrowing Hydrogen to Access Tricyclic Indoles. Angew Chem Int Ed Engl 2021; 60:20689-20694. [PMID: 34236747 DOI: 10.1002/anie.202106514] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/01/2021] [Indexed: 12/24/2022]
Abstract
An efficient tandem catalysis method is achieved for the direct conversion of alcohol-containing alkynyl anilines to valuable chiral 2,3-fused tricyclic indoles. This method relies on a tandem indolization followed by enantioconvergent substitution of alcohols via borrowing hydrogen to construct two rings in one step, enabled by relay and cooperative catalysis of a chiral iridium complex with a chiral phosphoric acid. Highly diastereoselective transformations of the tricyclic indole products also provide efficient access to a diverse array of complex polycyclic indoline compounds.
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Affiliation(s)
- Guoqiang Yang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Jiaoting Pan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.,Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China
| | - Ya-Ming Ke
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Yongbing Liu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Yu Zhao
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.,Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China
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28
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Bifunctional Borane Catalysis of a Hydride Transfer/Enantioselective [2+2] Cycloaddition Cascade. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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29
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Zhang C, Wang J, Su W, Lin Z, Ye Q. Synthesis, Characterization, and Density Functional Theory Studies of Three-Dimensional Inorganic Analogues of 9,10-Diboraanthracene-A New Class of Lewis Superacids. J Am Chem Soc 2021; 143:8552-8558. [PMID: 33984238 DOI: 10.1021/jacs.1c03057] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The three-dimensional inorganic analogues of 9,10-diboraanthracene, B2X2(C2B10H10)2 (X = Cl, 1; X = Br, 2), were attained by salt elimination of Li2C2B10H10 and trihaloboranes. The methyl- and phenyl-substituted compounds B2Me2(C2B10H10)2 (3) and B2Ph2(C2B10H10)2 (4) were obtained by treating 1 or 2 with the corresponding Grignard reagents. These compounds were fully characterized by NMR, cyclic voltammetry (CV), IR, and single-crystal X-ray diffraction analyses. Experimental (CV and Gutmann-Beckett method) and computational (fluoride ion affinity, hydride ion affinity and LUMO energy) results suggest that the order of Lewis acidity is 2 > 1 > 4 > 3 > SbF5. Treatment of 1 or 2 with HSiEt3 gave a rare neutral borane-silane adduct, (Et3SiH)2B2H2(C2B10H10)2 (5). The equilibrium of 5 in solution was thoroughly investigated by spectroscopy and quantum calculations.
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Affiliation(s)
- Chonghe Zhang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Junyi Wang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China.,Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Wei Su
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Qing Ye
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
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30
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Molnar M, Lončarić M, Jakovljević M, Komar M, Lončar M. Some applications of deep eutectic solvents in alkylation of heterocyclic compounds: A review of the past 10 years. HETEROCYCL COMMUN 2021. [DOI: 10.1515/hc-2020-0122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abstract
This mini-review encapsulates the latest findings (past 10 years) in the field of the deep eutectic solvents (DESs) application in the alkylation/arylation of different heterocyclic compounds. These solvents have been developed to fulfill the green chemistry concept demands and have been proven excellent for the application in various fields. This review describes their application in different types of alkylation, C-, N-, O- and S-alkylation. P-alkylation has not yet been published within this scope. Not only have the authors in this study proven that DESs could be successfully applied for this specific type of reaction, but they have also offered an excellent insight into the mechanisms of their action.
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Affiliation(s)
- Maja Molnar
- Department of Applied Chemistry and Ecology, Faculty of Food Technology Osijek , F. Kuhača 18 , 31000 Osijek , Croatia
| | - Melita Lončarić
- Department of Applied Chemistry and Ecology, Faculty of Food Technology Osijek , F. Kuhača 18 , 31000 Osijek , Croatia
| | - Martina Jakovljević
- Department of Applied Chemistry and Ecology, Faculty of Food Technology Osijek , F. Kuhača 18 , 31000 Osijek , Croatia
| | - Mario Komar
- Department of Applied Chemistry and Ecology, Faculty of Food Technology Osijek , F. Kuhača 18 , 31000 Osijek , Croatia
| | - Mirjana Lončar
- Department of Applied Chemistry and Ecology, Faculty of Food Technology Osijek , F. Kuhača 18 , 31000 Osijek , Croatia
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31
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Fang H, Xie K, Kemper S, Oestreich M. Aufeinanderfolgende β,β′‐selektive C(sp
3
)‐H‐Silylierung von tertiären Aminen mit Dihydrosilanen katalysiert durch B(C
6
F
5
)
3. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016664] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Huaquan Fang
- Institut für Chemie Technische Universität Berlin Straße des 17. Juni 115 10623 Berlin Deutschland
| | - Kaixue Xie
- Institut für Chemie Technische Universität Berlin Straße des 17. Juni 115 10623 Berlin Deutschland
| | - Sebastian Kemper
- Institut für Chemie Technische Universität Berlin Straße des 17. Juni 115 10623 Berlin Deutschland
| | - Martin Oestreich
- Institut für Chemie Technische Universität Berlin Straße des 17. Juni 115 10623 Berlin Deutschland
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32
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Fang H, Xie K, Kemper S, Oestreich M. Consecutive β,β'-Selective C(sp 3 )-H Silylation of Tertiary Amines with Dihydrosilanes Catalyzed by B(C 6 F 5 ) 3. Angew Chem Int Ed Engl 2021; 60:8542-8546. [PMID: 33604987 PMCID: PMC8048813 DOI: 10.1002/anie.202016664] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/16/2021] [Indexed: 01/05/2023]
Abstract
Tris(pentafluorophenyl)borane has been found to catalyze the two-fold C(sp3 )-H silylation of various trialkylamine derivatives with dihydrosilanes, furnishing the corresponding 4-silapiperidines in decent yields. The multi-step reaction cascade involves amine-to-enamine dehydrogenation at two alkyl residues and two electrophilic silylation reactions of those enamines, one inter- and one intramolecular.
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Affiliation(s)
- Huaquan Fang
- Institut für ChemieTechnische Universität BerlinStrasse des 17. Juni 11510623BerlinGermany
| | - Kaixue Xie
- Institut für ChemieTechnische Universität BerlinStrasse des 17. Juni 11510623BerlinGermany
| | - Sebastian Kemper
- Institut für ChemieTechnische Universität BerlinStrasse des 17. Juni 11510623BerlinGermany
| | - Martin Oestreich
- Institut für ChemieTechnische Universität BerlinStrasse des 17. Juni 11510623BerlinGermany
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33
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Kumar G, Roy S, Chatterjee I. Tris(pentafluorophenyl)borane catalyzed C-C and C-heteroatom bond formation. Org Biomol Chem 2021; 19:1230-1267. [PMID: 33481983 DOI: 10.1039/d0ob02478c] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A series of boron based Lewis acids have been reported to date, but among them, tris(pentafluorophenyl)borane (BCF) has gained the most significant attention in the synthetic chemistry community. The viability of BCF as a potential Lewis acid catalyst has been vastly explored in organic and materials chemistry due to its thermal stability and commercial availability. Most explorations of BCF chemistry in organic synthesis has occurred in the last two decades and many new catalytic reactivities are currently under investigation. This review mainly focuses on recent reports from 2018 onwards and provides a concise knowledge to the readers about the role of BCF in metal-free catalysis. The review has mainly been categorized by different types of organic transformation mediated through BCF catalysis for the C-C and C-heteroatom bond formation.
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Affiliation(s)
- Gautam Kumar
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
| | - Sourav Roy
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
| | - Indranil Chatterjee
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
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34
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Ma Y, Lou SJ, Hou Z. Electron-deficient boron-based catalysts for C-H bond functionalisation. Chem Soc Rev 2021; 50:1945-1967. [PMID: 33325932 DOI: 10.1039/d0cs00380h] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In contrast to transition metal-catalysed C-H functionalisation, highly efficient construction of C-C and C-X (X = N, O, S, B, Si, etc.) bonds through metal-free catalytic C-H functionalisation remains one of the most challenging tasks for synthetic chemists. In recent years, electron-deficient boron-based catalyst systems have exhibited great potential for C-H bond transformations. Such emerging systems may greatly enrich the chemistry of C-H functionalisation and main-group element catalysis, and will also provide enormous opportunities in synthetic chemistry, materials chemistry, and chemical biology. This article aims to give a timely comprehensive overview to recognise the current status of electron-deficient boron-based catalysis in C-H functionalisation and stimulate the development of more efficient catalytic systems.
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Affiliation(s)
- Yuanhong Ma
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine (Ministry of Educational of China), Key Laboratory of Phytochemistry R&D of Hunan Province, and Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.
| | - Shao-Jie Lou
- Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Zhaomin Hou
- Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. and Organometallic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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35
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Hughes-Whiffing CA, Perry A. One-pot, three-component Fischer indolisation- N-alkylation for rapid synthesis of 1,2,3-trisubstituted indoles. Org Biomol Chem 2021; 19:627-634. [PMID: 33367375 DOI: 10.1039/d0ob02185g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A one-pot, three-component protocol for the synthesis of 1,2,3-trisubstituted indoles has been developed, based upon a Fischer indolisation-indole N-alkylation sequence. This procedure is very rapid (total reaction time under 30 minutes), operationally straightforward, generally high yielding and draws upon readily available building blocks (aryl hydrazines, ketones, alkyl halides) to generate densely substituted indole products. We have demonstrated the utility of this process in the synthesis of 23 indoles, benzoindoles and tetrahydrocarbazoles bearing varied and useful functionality.
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Affiliation(s)
| | - Alexis Perry
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
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36
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He Y, Yang J, Zhang X, Fan X. Selective cleavage and reconstruction of C–N/C–C bonds in saturated cyclic amines: tunable synthesis of lactams and functionalized acyclic amines. Org Chem Front 2021. [DOI: 10.1039/d1qo00689d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective cleavage of C–N/C–C bonds in saturated cyclic amines for the tunable synthesis of lactams and functionalized acyclic amines under the promotion of oxoammonium salt and TBHP in the presence of different additives have been developed.
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Affiliation(s)
- Yan He
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Jintao Yang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xinying Zhang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xuesen Fan
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Environment, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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37
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He Y, Zheng Z, Yang J, Zhang X, Fan X. Recent advances in the functionalization of saturated cyclic amines. Org Chem Front 2021. [DOI: 10.1039/d1qo00171j] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Functionalized cyclic amines are the essential structural moieties of numerous biologically active compounds. This review summarized the most recent advances in the C–H, C–N and C–C bond functionalization of saturated cyclic amines.
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Affiliation(s)
- Yan He
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug
- Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control
- Ministry of Education
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- School of Environment
| | - Zhi Zheng
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug
- Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control
- Ministry of Education
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- School of Environment
| | - Jintao Yang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug
- Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control
- Ministry of Education
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- School of Environment
| | - Xinying Zhang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug
- Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control
- Ministry of Education
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- School of Environment
| | - Xuesen Fan
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug
- Key Laboratory for Yellow River and Huai River Water Environmental Pollution Control
- Ministry of Education
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- School of Environment
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38
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An XD, Xiao J. Recent advances in hydride transfer-involved C(sp3)–H activation reactions. Org Chem Front 2021. [DOI: 10.1039/d0qo01502d] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This review summarizes the recent progresses (2016–2020) in the hydride transfer-enabled C(sp3)–H activation according to the reaction types, categorized into the intramolecular/intermolecular C(sp3)–H functionalization, and hydride reduction.
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Affiliation(s)
- Xiao-De An
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao 266109
- China
| | - Jian Xiao
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao 266109
- China
- College of Marine Science and Engineering
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39
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Basak S, Winfrey L, Kustiana BA, Melen RL, Morrill LC, Pulis AP. Electron deficient borane-mediated hydride abstraction in amines: stoichiometric and catalytic processes. Chem Soc Rev 2021; 50:3720-3737. [DOI: 10.1039/d0cs00531b] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Borane mediated hydride abstraction of amines efficiently generates useful iminium salts. This review explores this fascinating reactivity and discusses how the iminium intermediates are utilised in a variety of stoichiometric and catalytic processes.
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Affiliation(s)
- Shyam Basak
- Cardiff Catalysis Institute
- School of Chemistry
- Cardiff University
- Cardiff
- UK
| | - Laura Winfrey
- School of Chemistry
- University of Leicester
- Leicester
- UK
| | - Betty A. Kustiana
- Cardiff Catalysis Institute
- School of Chemistry
- Cardiff University
- Cardiff
- UK
| | - Rebecca L. Melen
- Cardiff Catalysis Institute
- School of Chemistry
- Cardiff University
- Cardiff
- UK
| | - Louis C. Morrill
- Cardiff Catalysis Institute
- School of Chemistry
- Cardiff University
- Cardiff
- UK
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40
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Chen Y, Wan HL, Huang Y, Liu S, Wang F, Lu C, Nie J, Chen Z, Yang G, Ma C. B(C6F5)3-Catalyzed β-Functionalization of Pyrrolidines Using Isatins via Borrowing Hydrogen: Divergent Access to Substituted Pyrrolidines and Pyrroles. Org Lett 2020; 22:7797-7803. [DOI: 10.1021/acs.orglett.0c02600] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yong Chen
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Hai-Lun Wan
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Yuan Huang
- School of Pharmacy, Xi’an Jiaotong University, No. 76, Yanta West Road, Xi’an 710061, P.R. China
| | - Song Liu
- Chongqing Key Laboratory of Environmental Materials and Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing 402160, P.R. China
| | - Feiyi Wang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Cuifen Lu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Junqi Nie
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Zuxing Chen
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Guichun Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
| | - Chao Ma
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, College of Chemistry and Chemical Engineering, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, P.R. China
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41
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Chan JZ, Yesilcimen A, Cao M, Zhang Y, Zhang B, Wasa M. Direct Conversion of N-Alkylamines to N-Propargylamines through C-H Activation Promoted by Lewis Acid/Organocopper Catalysis: Application to Late-Stage Functionalization of Bioactive Molecules. J Am Chem Soc 2020; 142:16493-16505. [PMID: 32830966 PMCID: PMC8048775 DOI: 10.1021/jacs.0c08599] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
An efficient catalytic method to convert an α-C-H bond of N-alkylamines into an α-C-alkynyl bond was developed. In the past, such transformations were carried out under oxidative conditions, and the enantioselective variants were confined to tetrahydroisoquinoline derivatives. Here, we disclose a method for the union of N-alkylamines and trimethylsilyl alkynes, without the presence of an external oxidant and promoted through cooperative actions of two Lewis acids, B(C6F5)3 and a Cu-based complex. A variety of propargylamines can be synthesized in high diastereo- and enantioselectivity. The utility of the approach is demonstrated by the late-stage site-selective modification of bioactive amines. Kinetic investigations that shed light on various mechanistic nuances of the catalytic process are presented.
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Affiliation(s)
| | | | - Min Cao
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Yuyang Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Bochao Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Masayuki Wasa
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
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42
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Zhang J, Chang S. cine-Silylative Ring-Opening of α-Methyl Azacycles Enabled by the Silylium-Induced C-N Bond Cleavage. J Am Chem Soc 2020; 142:12585-12590. [PMID: 32627547 DOI: 10.1021/jacs.0c05241] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Described herein is the development of a borane-catalyzed cine-silylative ring-opening of α-methyl azacycles. This transformation involves four-step cascade processes: (i) exo-dehydrogenation of alicyclic amine, (ii) hydrosilylation of the resultant enamine, (iii) silylium-induced cis-β-amino elimination to open the ring skeleton, and (iv) hydrosilylation of the terminal olefin. The present borane catalysis also works efficiently for the C-N bond cleavage of acyclic tertiary amines. On the basis of experimental and computational studies, the silicon atom was elucidated to play a pivotal role in the β-amino elimination step.
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Affiliation(s)
- Jianbo Zhang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science & Technology (KAIST), Daejeon 34141, South Korea
| | - Sukbok Chang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science & Technology (KAIST), Daejeon 34141, South Korea
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