1
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Tao Q, Zheng Y, Li Q, Long Y, Wang J, Jin Z, Zhou X. Aerobic Reconstruction of Amines to Amides: A C-N/C-C Bond Cleavage Approach. Org Lett 2024. [PMID: 39680724 DOI: 10.1021/acs.orglett.4c04366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2024]
Abstract
Herein, an aerobic reconstruction of amines to amides via C(sp3)-N bond and C(sp2)-C(sp3) bond cleavage is described. This method features a metal-free reaction, insensitivity to oxygen or moisture, and ambient air as the terminal oxidant. Preliminary mechanistic studies suggest that the reaction pathway of amine oxidation, followed by imine exchange and Beckmann rearrangement, is involved.
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Affiliation(s)
- Qinyue Tao
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Yanling Zheng
- School of Pharmacy, North Sichuan Medical College, Nanchong 637000, P. R. China
| | - Qiang Li
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Yang Long
- School of Pharmacy, North Sichuan Medical College, Nanchong 637000, P. R. China
| | - Jing Wang
- Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610064, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zewei Jin
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Xiangge Zhou
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
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2
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Amber C, Göttemann LT, Steele RT, Petitjean TM, Sarpong R. Reductive Amination of Carbonyl C-C Bonds Enables Formal Nitrogen Insertion. J Org Chem 2024; 89:17655-17663. [PMID: 39509344 PMCID: PMC11624976 DOI: 10.1021/acs.joc.4c02400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2024]
Abstract
Given its relevance across numerous fields, reductive amination is one of the oldest and most widely used methods for amine synthesis. As a cornerstone of synthetic chemistry, it has largely remained unchanged since its discovery over a century ago. Herein, we report the mechanistically driven development of a complementary reaction, which reductively aminates the C-C σ-bond of carbonyls, not the carbonyl C-O π-bond, generating value-added linear and cyclic 3° amines in a modular fashion. Critical to our success were mechanistic insights that enabled us to modulate the resting state of a borane catalyst, minimize deleterious disproportionation of a hydroxylamine nitrogen source, and control the migratory selectivity of a key nitrenoid reactive intermediate. Experiments support the reaction occurring through a reductive amination/reductive Stieglitz cascade, via a ketonitrone, which can be interrupted under catalyst control to generate valuable N,N-disubstituted hydroxylamines. The method reported herein enables net transformations that would otherwise require lengthy synthetic sequences using pre-existing technologies. This is highlighted by its application to a two-step protocol for the valorization of hydrocarbon feedstocks, the late-stage C-C amination of complex molecules, diversity-oriented synthesis of isomeric amines from a single precursor, and transposition of nitrogen to different positions within a heterocycle.
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Affiliation(s)
- Charis Amber
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Lucas T Göttemann
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Ryan T Steele
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Timothée M Petitjean
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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3
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Ma P, Guo T, Lu H. Hydro- and deutero-deamination of primary amines using O-diphenylphosphinylhydroxylamine. Nat Commun 2024; 15:10190. [PMID: 39582045 PMCID: PMC11586428 DOI: 10.1038/s41467-024-54599-y] [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: 08/22/2024] [Accepted: 11/18/2024] [Indexed: 11/26/2024] Open
Abstract
While selective defunctionalizations are valuable in organic synthesis, hydrodeamination of primary amines poses challenges. Deuterodeamination, analogous to hydrodeamination, presents even greater difficulties due to its frequently slower deuteration rate, interference by hydrogenation and constraints in deuterated sources. This study introduces a reliable, robust, and scalable hydro- and deuterodeamination method capable of handling various primary amines. Defined by its mild reaction conditions, rapid completion, simplified purification facilitated by water-soluble byproducts, the method leverages deuterium oxide as a deuterium source and employs commercialized O-diphenylphosphinylhydroxylamine for deamination. Applied to a diverse range of biologically active molecules, it has consistently achieved high yields and efficient deuterium incorporation. By synergizing with site-selective C-H functionalization of primary aliphatic amines, our method reveals synthetic strategies utilizing nitrogen atom as a traceless directing group, encompassing deaminative alkylation, 1,1-deuteroalkylation, 1,1-dialkylation, 1,1,1-deuterodialkylation, C-H arylation, and 1,3-deuteroarylation. Emphasizing this innovation, the processes of deaminative degree-controlled deuteration have been developed.
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Affiliation(s)
- Panpan Ma
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Ting Guo
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Hongjian Lu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
- The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu, Anhui, China.
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4
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Davison N, Hemingway JM, Wills C, Stolar T, Waddell PG, Dixon CM, Barron L, Dawson JA, Lu E. Mechanochemical Synthesis of a Sodium Anion Complex [Na +(2,2,2-cryptand)Na -] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions. Inorg Chem 2024; 63:15247-15258. [PMID: 39069662 PMCID: PMC11323275 DOI: 10.1021/acs.inorgchem.4c02914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Revised: 07/20/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is -1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na+(2,2,2-cryptand)Na-], which allows us to unveil a versatile reactivity profile of this once exotic species.
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Affiliation(s)
- Nathan Davison
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Jack M. Hemingway
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Corinne Wills
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Tomislav Stolar
- Federal
Institute for Materials Research and Testing (BAM), 12489 Berlin, Germany
| | - Paul G. Waddell
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Casey M. Dixon
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Luke Barron
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - James A. Dawson
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Erli Lu
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
- Chemistry,
School of Natural and Environmental Sciences, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
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5
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Jiao Z, Jaunich KT, Tao T, Gottschall O, Hughes MM, Turlik A, Schuppe AW. Unified Approach to Deamination and Deoxygenation Through Isonitrile Hydrodecyanation: A Combined Experimental and Computational Investigation. Angew Chem Int Ed Engl 2024; 63:e202405779. [PMID: 38619535 DOI: 10.1002/anie.202405779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/13/2024] [Accepted: 04/15/2024] [Indexed: 04/16/2024]
Abstract
Herein, we describe a general hydrodefunctionalization protocol of alcohols and amines through a common isonitrile intermediate. To cleave the relatively inert C-NC bond, we leveraged dual hydrogen atom transfer (HAT) and photoredox catalysis to generate a nucleophilic boryl radical, which readily forms an imidoyl radical intermediate from the isonitrile. Rapid β-scission then accomplishes defunctionalization. This method has been applied to the hydrodefunctionalization of both amine and alcohol-containing pharmaceuticals, natural products, and biomolecules. We extended this approach to the reduction of carbonyls and olefins to their saturated counterparts, as well as the hydrodecyanation of alkyl nitriles. Both experimental and computational studies demonstrate a facile β-scission of the imidoyl radical, and reconcile differences in reactivity between nitriles and isonitriles within our protocol.
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Affiliation(s)
- Ziqi Jiao
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Kyle T Jaunich
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Thomas Tao
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Olivia Gottschall
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Maxwell M Hughes
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Aneta Turlik
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Alexander W Schuppe
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
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6
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Ma YQ, Tian SK. Catalyst-free visible light-promoted defunctionalization of alkyl isocyanides with a hydrosilane through C-N bond cleavage. Org Biomol Chem 2024; 22:2562-2565. [PMID: 38451158 DOI: 10.1039/d4ob00173g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
A radical initiator-free defunctionalization reaction of alkyl isocyanides with a hydrosilane has been established through C-N bond cleavage under catalyst-free visible light irradiation. Various alkyl isocyanides participated in the defunctionalization with tris(trimethylsilyl)silane under blue light irradiation at room temperature, delivering the reduced products in good yields with high chemoselectivity.
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Affiliation(s)
- Yu-Qing Ma
- Hefei National Research Center for Physical Sciences at the Microscale, Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Shi-Kai Tian
- Hefei National Research Center for Physical Sciences at the Microscale, Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
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7
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Quirós I, Martín M, Gomez-Mendoza M, Cabrera-Afonso MJ, Liras M, Fernández I, Nóvoa L, Tortosa M. Isonitriles as Alkyl Radical Precursors in Visible Light Mediated Hydro- and Deuterodeamination Reactions. Angew Chem Int Ed Engl 2024; 63:e202317683. [PMID: 38150265 DOI: 10.1002/anie.202317683] [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: 11/20/2023] [Revised: 12/20/2023] [Accepted: 12/27/2023] [Indexed: 12/28/2023]
Abstract
Herein, we report the use of isonitriles as alkyl radical precursors in light-mediated hydro- and deuterodeamination reactions. The reaction is scalable, shows broad functional group compatibility and potential to be used in late-stage functionalization. Importantly, the method is general for Cα -primary, Cα -secondary and Cα -tertiary alkyl isonitriles. For most examples, high yields were obtained through direct visible-light irradiation of the isonitrile in the presence of a silyl radical precursor. Interestingly, in the presence of an organic photocatalyst (4CzIPN) a dramatic acceleration was observed. In-depth mechanistic studies using UV/Vis absorption, steady-state and time-resolved photoluminescence, and transient absorption spectroscopy suggest that the excited state of 4CzIPN can engage in a single-electron transfer with the isonitrile.
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Affiliation(s)
- Irene Quirós
- Organic Chemistry Department, Universidad Autónoma de Madrid (UAM), Avda. Francisco Tomás y Valiente 7, Cantoblanco, 28049, Madrid, Spain
| | - María Martín
- Organic Chemistry Department, Universidad Autónoma de Madrid (UAM), Avda. Francisco Tomás y Valiente 7, Cantoblanco, 28049, Madrid, Spain
| | - Miguel Gomez-Mendoza
- Photoactivated Processes Unit, IMDEA Energy, Av. Ramón de la Sagra 3, Móstoles, 28935, Madrid, Spain
| | - María Jesús Cabrera-Afonso
- Organic Chemistry Department, Universidad Autónoma de Madrid (UAM), Avda. Francisco Tomás y Valiente 7, Cantoblanco, 28049, Madrid, Spain
| | - Marta Liras
- Photoactivated Processes Unit, IMDEA Energy, Av. Ramón de la Sagra 3, Móstoles, 28935, Madrid, Spain
| | - Israel Fernández
- Department of Organic Chemistry, Faculty of Chemistry, Complutense University of Madrid, 28040, Madrid, Spain
- Center of Innovation in Advanced Chemistry (ORFEO-CINQA), Spain
| | - Luis Nóvoa
- Organic Chemistry Department, Universidad Autónoma de Madrid (UAM), Avda. Francisco Tomás y Valiente 7, Cantoblanco, 28049, Madrid, Spain
| | - Mariola Tortosa
- Organic Chemistry Department, Universidad Autónoma de Madrid (UAM), Avda. Francisco Tomás y Valiente 7, Cantoblanco, 28049, Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid (UAM), Avda. Francisco Tomás y Valiente 7, Cantoblanco, 28049, Madrid, Spain
- Center of Innovation in Advanced Chemistry (ORFEO-CINQA), Spain
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8
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Su X, Wang Y, Feng Q, Sun J. Heterodifunctionalization of Electron-Rich Alkynes Catalyzed by in Situ Generated Silylium Ions. Org Lett 2024; 26:421-426. [PMID: 38166166 DOI: 10.1021/acs.orglett.3c04208] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Silylium ions are versatile Lewis acids in organic synthesis. While they have been well-known for the activation of σ donors, catalysis initiated by the activation of π donors remains underdeveloped, particularly for alkynes. Herein, we demonstrate an example of silylium-catalyzed alkyne heterodifunctionalization. The silylium ion generated in situ from HNTf2 and the silyl reagent serve as superior catalysts in the efficient silylphosphination and silylcyanation of electron-rich alkynes with excellent regio- and stereoselectivity. The compatibility of this protocol with strongly coordinating ligands (Ph2P and CN) not only complements the metal-catalyzed systems but also expands the scope of silylium-catalyzed reactions.
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Affiliation(s)
- Xiang Su
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Yong Wang
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China
| | - Qiang Feng
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China
| | - Jianwei Sun
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China
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9
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Zhang J, Chen Z, Chen M, Zhou Q, Zhou R, Wang W, Shao Y, Zhang F. Lanthanide/B(C 6F 5) 3-Promoted Hydroboration Reduction of Indoles and Quinolines with Pinacolborane. J Org Chem 2024. [PMID: 38178689 DOI: 10.1021/acs.joc.3c01767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
We have developed a lanthanide/B(C6F5)3-promoted hydroboration reduction of indoles and quinolines with pinacolborane (HBpin). This reaction provides streamlined access to a range of nitrogen-containing compounds in moderate to excellent yields. Large-scale synthesis and further transformations to bioactive compounds indicate that the method has potential practical applications. Preliminary mechanistic studies suggest that amine additives promote the formation of indole-borane intermediates, and the lanthanide/B(C6F5)3-promoted hydroboration reduction proceeds via hydroboration of indole-borane intermediates with HBpin and in situ-formed BH3 species, followed by the protodeborylation process.
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Affiliation(s)
- Jianping Zhang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Ziyan Chen
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Mingxin Chen
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Qi Zhou
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Rongrong Zhou
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Wenli Wang
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Yinlin Shao
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
- Institute of New Materials & Industrial Technology, Wenzhou University, Wenzhou 325035, China
| | - Fangjun Zhang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
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10
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Deaminative bromination, chlorination, and iodination of primary amines. iScience 2023; 26:106255. [PMID: 36909668 PMCID: PMC9993034 DOI: 10.1016/j.isci.2023.106255] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/06/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
The primary amino group has been seldom utilized as a transformable functionality in organic synthesis. Reported herein is a deaminative halogenation of primary amines using N-anomeric amide as the nitrogen-deletion reagent. Both aliphatic and aromatic amines are competent substrates for direct halogenations. The mildness and robustness of the protocol are evidenced by the successful reactions of several complex- and functional group-enriched bioactive compounds or drugs. Elaboration of the resulting products provides interesting analogues of drug molecules.
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11
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Peng Y, Oestreich M. B(C 6 F 5 ) 3 -Catalyzed Regioselective Ring Opening of Cyclic Amines with Hydrosilanes. Chemistry 2023; 29:e202203721. [PMID: 36448647 DOI: 10.1002/chem.202203721] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/02/2022]
Abstract
Opening the ring of cyclic amines by regioselective fission of one of the carbon-nitrogen bonds greatly expands the repertoire of available nitrogen-containing skeletons. Unlike approaches starting from cyclic tertiary amines, methods that can directly open secondary amines are still scarce. The present work discloses an efficient reductive ring opening of either of these cyclic amines using PhSiH3 under B(C6 F5 )3 catalysis. By this, the direct transformation of unstrained cyclic amines into the corresponding acyclic amines is achieved in a simple one-pot operation. A stepwise mechanism proceeding through the intermediacy of silylammonium ions followed by reductive cleavage of a carbon-nitrogen bond was experimentally verified.
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Affiliation(s)
- Yi Peng
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623, Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623, Berlin, Germany
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12
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Beck AD, Haufe S, Waldvogel SR. General Concepts and Recent Advances in the Electrochemical Transformation of Chloro‐ and Hydrosilanes. ChemElectroChem 2023. [DOI: 10.1002/celc.202201149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Alexander D. Beck
- Wacker Chemie AG Consortium für elektrochemische Industrie Zielstattstraße 20 81379 München Germany
- Department Chemie Johannes Gutenberg-Universität Mainz Duesbergweg 10–14 55128 Mainz Germany
| | - Stefan Haufe
- Wacker Chemie AG Consortium für elektrochemische Industrie Zielstattstraße 20 81379 München Germany
| | - Siegfried R. Waldvogel
- Department Chemie Johannes Gutenberg-Universität Mainz Duesbergweg 10–14 55128 Mainz Germany
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13
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Zheng L, Mei W, Zou X, Zhong Y, Wu Y, Deng L, Wang Y, Yang B, Guo W. DBU-Promoted Deaminative Thiolation of 1 H-Benzo[ d]imidazol-2-amines and Benzo[ d]oxazol-2-amines. J Org Chem 2023; 88:272-284. [PMID: 36521048 DOI: 10.1021/acs.joc.2c02297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A facile and efficient catalyst-/metal-/oxidant-free DBU-promoted deaminative thiolation reaction of 1H-benzo[d]imidazol-2-amines and benzo[d]oxazol-2-amines has been developed at room temperature conditions in a one-pot protocol. This practical three-component strategy represents a novel and environmentally friendly reaction pathway toward the straightforward synthesis of various 2-thio-1H-benzo[d]imidazoles and 2-thiobenzo[d]oxazoles using carbon disulfide as a sulfur source through C-N bond cleavage and C-S bond formation process. Different types of 1H-benzo[d]imidazol-2-amines, benzo[d]oxazol-2-amines, and organic bromides are suitable substrates. The gram-scale and late-stage modification experiments provide the potential applications based on this methodology in the field of organic and medicinal chemistry.
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Affiliation(s)
- Lvyin Zheng
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Weijie Mei
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Xiaoying Zou
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yumei Zhong
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yingying Wu
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Lei Deng
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yihan Wang
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Beining Yang
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Wei Guo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
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14
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Zhou M, Wang T, Cheng GJ. Mechanistic insights into reductive deamination with hydrosilanes catalyzed by B(C6F5)3: A DFT study. Front Chem 2022; 10:1025135. [DOI: 10.3389/fchem.2022.1025135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 09/20/2022] [Indexed: 11/18/2022] Open
Abstract
Selective defunctionalization of synthetic intermediates is a valuable approach in organic synthesis. Here, we present a theoretical study on the recently developed B(C6F5)3/hydrosilane-mediated reductive deamination reaction of primary amines. Our computational results provide important insights into the reaction mechanism, including the active intermediate, the competing reactions of the active intermediate, the role of excess hydrosilane, and the origin of chemoselectivity. Moreover, the study on the substituent effect of hydrosilane indicated a potential way to improve the efficiency of the reductive deamination reaction.
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15
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Ríos P, Rodríguez A, Conejero S. Activation of Si-H and B-H bonds by Lewis acidic transition metals and p-block elements: same, but different. Chem Sci 2022; 13:7392-7418. [PMID: 35872827 PMCID: PMC9241980 DOI: 10.1039/d2sc02324e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/18/2022] [Indexed: 01/01/2023] Open
Abstract
In this Perspective we discuss the ability of transition metal complexes to activate and cleave the Si-H and B-H bonds of hydrosilanes and hydroboranes (tri- and tetra-coordinated) in an electrophilic manner, avoiding the need for the metal centre to undergo two-electron processes (oxidative addition/reductive elimination). A formal polarization of E-H bonds (E = Si, B) upon their coordination to the metal centre to form σ-EH complexes (with coordination modes η1 or η2) favors this type of bond activation that can lead to reactivities involving the formation of transient silylium and borenium/boronium cations similar to those proposed in silylation and borylation processes catalysed by boron and aluminium Lewis acids. We compare the reactivity of transition metal complexes and boron/aluminium Lewis acids through a series of catalytic reactions in which pieces of evidence suggest mechanisms involving electrophilic reaction pathways.
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Affiliation(s)
- Pablo Ríos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica CSIC and Universidad de Sevilla, Centro de Innovación en Química Avanzada (ORFEO-CINQA) C/Américo Vespucio 49 41092 Sevilla Spain
| | - Amor Rodríguez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica CSIC and Universidad de Sevilla, Centro de Innovación en Química Avanzada (ORFEO-CINQA) C/Américo Vespucio 49 41092 Sevilla Spain
| | - Salvador Conejero
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica CSIC and Universidad de Sevilla, Centro de Innovación en Química Avanzada (ORFEO-CINQA) C/Américo Vespucio 49 41092 Sevilla Spain
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16
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Wohlgemuth R. Selective Biocatalytic Defunctionalization of Raw Materials. CHEMSUSCHEM 2022; 15:e202200402. [PMID: 35388636 DOI: 10.1002/cssc.202200402] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Biobased raw materials, such as carbohydrates, amino acids, nucleotides, or lipids contain valuable functional groups with oxygen and nitrogen atoms. An abundance of many functional groups of the same type, such as primary or secondary hydroxy groups in carbohydrates, however, limits the synthetic usefulness if similar reactivities cannot be differentiated. Therefore, selective defunctionalization of highly functionalized biobased starting materials to differentially functionalized compounds can provide a sustainable access to chiral synthons, even in case of products with fewer functional groups. Selective defunctionalization reactions, without affecting other functional groups of the same type, are of fundamental interest for biocatalytic reactions. Controlled biocatalytic defunctionalizations of biobased raw materials are attractive for obtaining valuable platform chemicals and building blocks. The biocatalytic removal of functional groups, an important feature of natural metabolic pathways, can also be utilized in a systemic strategy for sustainable metabolite synthesis.
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Affiliation(s)
- Roland Wohlgemuth
- Institute of Molecular and Industrial Biotechnology, Lodz University of Technology Łódź, 90-537, Lodz, Poland
- Swiss Coordination Committee Biotechnology (SKB), 8002, Zurich, Switzerland
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17
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Peng Y, Oestreich M. B(C 6F 5) 3-Catalyzed Reductive Denitrogenation of Benzonitrile Derivatives. Org Lett 2022; 24:2940-2943. [PMID: 35417183 DOI: 10.1021/acs.orglett.2c01003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A B(C6F5)3-catalyzed reductive denitrogenation of aromatic nitriles is reported, achieving the metal-free transformation of a cyano into a methyl group in a single synthetic operation. Tris(phenylsilyl)amine is liberated as the nitrogen-containing byproduct. On the basis of control experiments as well as a nuclear magnetic resonance spectroscopic analysis, an SN1-type mechanism involving a trisilylammonium ion as a key intermediate is proposed.
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Affiliation(s)
- Yi Peng
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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18
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19
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Abstract
In the last two decades, boron-based catalysis has been gaining increasing traction in the field of organic synthesis. The use of halogenated triarylboranes as main group Lewis acid catalysts is an attractive strategy. It has been applied in a growing number of transformations over the years, where they may perform comparably or even better than the gold standard catalysts. This review discusses methods of borane synthesis and cutting-edge boron-based Lewis acid catalysis, focusing especially on tris(pentafluorophenyl)-borane [B(C6F5)3], and other halogenated triarylboranes, highlighting how boron Lewis acids employed as catalysts can unlock a plethora of unprecedented chemical transformations or improve the efficiency of existing reactions.
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20
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Struwe J, Korvorapun K, Zangarelli A, Ackermann L. Photo-Induced Ruthenium-Catalyzed C-H Benzylations and Allylations at Room Temperature. Chemistry 2021; 27:16237-16241. [PMID: 34435716 PMCID: PMC9293244 DOI: 10.1002/chem.202103077] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Indexed: 11/30/2022]
Abstract
The ruthenium-catalyzed synthesis of diarylmethane compounds was realized under exceedingly mild photoredox conditions without the use of exogenous photocatalysts. The versatility and robustness of the ruthenium-catalyzed C-H benzylation was reflected by an ample scope, including multifold C-H functionalizations, as well as transformable pyrazoles, imidates and sensitive nucleosides. Mechanistic studies were indicative of a photoactive cyclometalated ruthenium complex, which also enabled versatile C-H allylations.
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Affiliation(s)
- Julia Struwe
- Institut für Organische und Biomolekulare ChemieGeorg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Korkit Korvorapun
- Institut für Organische und Biomolekulare ChemieGeorg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Agnese Zangarelli
- Institut für Organische und Biomolekulare ChemieGeorg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare ChemieGeorg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
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21
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Berger KJ, Driscoll JL, Yuan M, Dherange BD, Gutierrez O, Levin MD. Direct Deamination of Primary Amines via Isodiazene Intermediates. J Am Chem Soc 2021; 143:17366-17373. [PMID: 34637305 PMCID: PMC8892627 DOI: 10.1021/jacs.1c09779] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We report here a reaction that selectively deaminates primary amines and anilines under mild conditions and with remarkable functional group tolerance including a range of pharmaceutical compounds, amino acids, amino sugars, and natural products. An anomeric amide reagent is uniquely capable of facilitating the reaction through the intermediacy of an unprecedented monosubstituted isodiazene intermediate. In addition to dramatically simplifying deamination compared to existing protocols, our approach enables strategic applications of iminium and amine-directed chemistries as traceless methods. Mechanistic and computational studies support the intermedicacy of a primary isodiazene which exhibits an unexpected divergence from previously studied secondary isodiazenes, leading to cage-escaping, free radical species that engage in a chain, hydrogen-atom transfer process involving aliphatic and diazenyl radical intermediates.
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Affiliation(s)
- Kathleen J. Berger
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Julia L. Driscoll
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Mingbin Yuan
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Balu D. Dherange
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Osvaldo Gutierrez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States; Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Mark D. Levin
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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22
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Muramatsu W, Yamamoto H. Peptide Bond Formation of Amino Acids by Transient Masking with Silylating Reagents. J Am Chem Soc 2021; 143:6792-6797. [PMID: 33929829 DOI: 10.1021/jacs.1c02600] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A one-pot peptide bond-forming reaction has been developed using unprotected amino acids and peptides. Two different silylating reagents, HSi[OCH(CF3)2]3 and MTBSTFA, are instrumental for the successful implementation of this approach, being used for the activation and transient masking of unprotected amino acids and peptides at C-termini and N-termini, respectively. Furthermore, CsF and imidazole are used as catalysts, activating HSi[OCH(CF3)2]3 and also accelerating chemoselective silylation. This method is versatile as it tolerates side chains that bear a range of functional groups, while providing up to >99% yields of corresponding peptides without any racemization or polymerization.
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Affiliation(s)
- Wataru Muramatsu
- Molecular Catalyst Research Center, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
| | - Hisashi Yamamoto
- Molecular Catalyst Research Center, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
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23
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Duan S, Xue B, Meng H, Ye Z, Xu Z, Li C. Rhodium(
II
)‐Catalyzed [4+3] Cyclization of Triazoles with Indole Derivatives and Its Application in the Total Synthesis of (±)‐Aurantioclavine. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202000657] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shengguo Duan
- Department of Chemistry, Zhejiang Sci‐Tech University, Hangzhou Zhejiang 310018 China
| | - Bing Xue
- Department of Chemistry, Zhejiang Sci‐Tech University, Hangzhou Zhejiang 310018 China
| | - Hui Meng
- Department of Chemistry, Zhejiang Sci‐Tech University, Hangzhou Zhejiang 310018 China
| | - Zihang Ye
- Department of Chemistry, Zhejiang Sci‐Tech University, Hangzhou Zhejiang 310018 China
| | - Ze‐Feng Xu
- Department of Chemistry, Zhejiang Sci‐Tech University, Hangzhou Zhejiang 310018 China
| | - Chuan‐Ying Li
- Department of Chemistry, Zhejiang Sci‐Tech University, Hangzhou Zhejiang 310018 China
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24
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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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25
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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: 27] [Impact Index Per Article: 9.0] [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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26
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Berger KJ, Levin MD. Reframing primary alkyl amines as aliphatic building blocks. Org Biomol Chem 2021; 19:11-36. [PMID: 33078799 DOI: 10.1039/d0ob01807d] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While primary aliphatic amines are ubiquitous in natural products, they are traditionally considered inert to substitution chemistry. This review highlights historical and recent advances in the field of aliphatic deamination chemistry which demonstrate these moieties can be harnessed as valuable C(sp3) synthons. Cross-coupling and photocatalyzed transformations proceeding through polar and radical mechanisms are compared with oxidative deamination and other transition metal catalyzed reactions.
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Affiliation(s)
- Kathleen J Berger
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.
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27
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Fang H, Wang G, Oestreich M. Mild reductive rearrangement of oximes and oxime ethers to secondary amines with hydrosilanes catalyzed by B(C 6F 5) 3. Org Chem Front 2021. [DOI: 10.1039/d1qo00251a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Oximes, its ether derivatives and the corresponding hydroxylamines rearrange to secondary amines when reacted with PhSiH3 and B(C6F5)3 as catalyst. Computations suggest a reduction–rearrangement to be slightly favored over a Beckmann-type sequence.
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Affiliation(s)
- Huaquan Fang
- Institut für Chemie
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Guoqiang Wang
- Institut für Chemie
- Technische Universität Berlin
- 10623 Berlin
- Germany
- Institute of Theoretical and Computational Chemistry
| | - Martin Oestreich
- Institut für Chemie
- Technische Universität Berlin
- 10623 Berlin
- Germany
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28
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Jiao LY, Peng XH, Wang ZL, Jia N, Li Z. When phosphoryl azide meets mechanochemistry: clean, rapid, and efficient synthesis of phosphoryl amides under B(C6F5)3 catalysis in a ball mill. Catal Sci Technol 2021. [DOI: 10.1039/d1cy01314a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We described herein the first example associated with B(C6F5)3-catalyzed preparation of phosphoryl amides under mechanochemical conditions.
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Affiliation(s)
- Lin-Yu Jiao
- School of Chemical Engineering, Northwest University, Xi'an, Shaanxi, 710069, P. R. China
- International Scientific and Technological Cooperation Base for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advance Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an, Shaanxi, 710069, P. R. China
| | - Xin-Hua Peng
- School of Chemical Engineering, Northwest University, Xi'an, Shaanxi, 710069, P. R. China
| | - Ze-Lin Wang
- School of Chemical Engineering, Northwest University, Xi'an, Shaanxi, 710069, P. R. China
| | - Nan Jia
- School of Chemical Engineering, Northwest University, Xi'an, Shaanxi, 710069, P. R. China
| | - Zhuo Li
- School of Chemical Engineering, Northwest University, Xi'an, Shaanxi, 710069, P. R. China
- International Scientific and Technological Cooperation Base for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advance Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an, Shaanxi, 710069, P. R. China
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29
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Vidal F, McQuade J, Lalancette R, Jäkle F. ROMP-Boranes as Moisture-Tolerant and Recyclable Lewis Acid Organocatalysts. J Am Chem Soc 2020; 142:14427-14431. [PMID: 32787237 DOI: 10.1021/jacs.0c05454] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although widely used in catalysis, the multistep syntheses and high loadings typically employed are limiting broader implementation of highly active tailor-made arylborane Lewis acids and Lewis pairs. Attempts at developing recyclable systems have thus far met with limited success, as general and versatile platforms are yet to be developed. We demonstrate a novel approach that is based on the excellent control and functional group tolerance of ring-opening metathesis polymerization (ROMP). The ROMP of highly Lewis acidic borane-functionalized phenylnorbornenes afforded both a soluble linear copolymer and a cross-linked organogel. The polymers proved highly efficient as recyclable catalysts in the reductive N-alkylation of arylamines under mild conditions and at exceptionally low catalyst loadings. The modular design presented herein can be readily adapted to other finely tuned triarylboranes, enabling wide applications of ROMP-borane polymers as well-defined supported organocatalysts.
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Affiliation(s)
- Fernando Vidal
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
| | - James McQuade
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Roger Lalancette
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Frieder Jäkle
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
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30
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Fang H, Oestreich M. Defunctionalisation catalysed by boron Lewis acids. Chem Sci 2020; 11:12604-12615. [PMID: 34094457 PMCID: PMC8163203 DOI: 10.1039/d0sc03712e] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 07/22/2020] [Indexed: 12/22/2022] Open
Abstract
Selective defunctionalisation of organic molecules to valuable intermediates is a fundamentally important transformation in organic synthesis. Despite the advances made in efficient and selective defunctionalisation using transition-metal catalysis, the cost, toxicity, and non-renewable properties limit its application in industrial manufacturing processes. In this regard, boron Lewis acid catalysis has emerged as a powerful tool for the cleavage of carbon-heteroatom bonds. The ground-breaking finding is that the strong boron Lewis acid B(C6F5)3 can activate Si-H bonds through η1 coordination, and this Lewis adduct is a key intermediate that enables various reduction processes. This system can be tuned by variation of the electronic and structural properties of the borane catalyst, and together with different hydride sources high chemoselectivity can be achieved. This Perspective provides a comprehensive summary of various defunctionalisation reactions such as deoxygenation, decarbonylation, desulfurisation, deamination, and dehalogenation, all of which catalysed by boron Lewis acids.
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Affiliation(s)
- Huaquan Fang
- Institut für Chemie, Technische Universität Berlin Strasse des 17. Juni 115 10623 Berlin Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin Strasse des 17. Juni 115 10623 Berlin Germany
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31
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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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32
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Fang H, Oestreich M. Reductive Deamination with Hydrosilanes Catalyzed by B(C 6 F 5 ) 3. Angew Chem Int Ed Engl 2020; 59:11394-11398. [PMID: 32311213 PMCID: PMC7384015 DOI: 10.1002/anie.202004651] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/19/2020] [Indexed: 11/29/2022]
Abstract
The strong boron Lewis acid tris(pentafluorophenyl)borane B(C6 F5 )3 is known to catalyze the dehydrogenative coupling of certain amines and hydrosilanes at elevated temperatures. At higher temperature, the dehydrogenation pathway competes with cleavage of the C-N bond and defunctionalization is obtained. This can be turned into a useful methodology for the transition-metal-free reductive deamination of a broad range of amines as well as heterocumulenes such as an isocyanate and an isothiocyanate.
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Affiliation(s)
- Huaquan Fang
- Institut für ChemieTechnische Universität BerlinStrasse des 17. Juni 11510623BerlinGermany
| | - Martin Oestreich
- Institut für ChemieTechnische Universität BerlinStrasse des 17. Juni 11510623BerlinGermany
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