1
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Song M, Feng M, Li F, Lv S, Zhou Y, Chen Z. Electrosynthesis of Amides through Cu- and Co-Incorporated Nickel Hydroxide-Catalyzed Oxidation of Primary Amines Coupled with Hydrogen Evolution. Inorg Chem 2024; 63:15215-15223. [PMID: 39088415 DOI: 10.1021/acs.inorgchem.4c02797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2024]
Abstract
The electrocatalytic oxidation of organic molecules coupled with hydrogen evolution reaction can reduce overpotential and can be connected in series with nonelectrochemical processes to achieve the preparation of more high-value compounds. Herein, Cu- and Co-incorporated nickel hydroxide (CuCo-Ni(OH)2) was synthesized and applied to the anodic benzylamine oxidation reaction, which is 280 mV lower than the corresponding oxygen evolution reaction to reach the current density of 50 mA cm-2. When the electrocatalytic oxidation of benzylamine and hydrogen evolution reaction are coupled to form an electrolytic cell, the potential to reach 10 mA cm-2 is reduced by 197 mV compared to the overall water splitting. The benzylamine is converted to benzamide with 99.3% conversion and 90.2% faraday efficiency under 1.45 V constant voltage electrolysis, and the catalytic performance remains at a high level after 4 cycles. The characterization and density functional theory calculations show that Cu and Co share the transfer charge from Ni, making it easy for CuCo-Ni(OH)2 to deprotonate Ni-O* sites. The formed Ni-O* sites exhibit lower energy barriers in the proton transfer of benzylamine to benzonitrile and hydration intermediates, resulting in a better catalytic performance of CuCo-Ni(OH)2 than Ni(OH)2 in the electrocatalytic oxidation of benzylamine to benzamide.
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Affiliation(s)
- Manman Song
- Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Mengmeng Feng
- Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Feng Li
- Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Shanshan Lv
- Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Yan Zhou
- Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Zheng Chen
- Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, China
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2
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Ramachandran PV, Singh A, Walker H, Hamann HJ. Borane-Pyridine: An Efficient Catalyst for Direct Amidation. Molecules 2024; 29:268. [PMID: 38202849 PMCID: PMC10780903 DOI: 10.3390/molecules29010268] [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: 12/01/2023] [Revised: 12/21/2023] [Accepted: 12/26/2023] [Indexed: 01/12/2024] Open
Abstract
Borane-pyridine acts as an efficient (5 mol%) liquid catalyst, providing improved solubility for the direct amidation of a wide range of aromatic and aliphatic carboxylic acids and amines to form secondary and tertiary carboxamides. Tolerance of potentially incompatible halo, nitro, and alkene functionalities has been demonstrated.
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3
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Ramachandran PV, Choudhary S. One-Pot, Tandem Reductive Amination/Alkylation-Cycloamidation for Lactam Synthesis from Keto or Amino Acids. J Org Chem 2023; 88:15956-15963. [PMID: 37932035 DOI: 10.1021/acs.joc.3c01126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Monotrifluoroacetoxyborane-amines, prepared by treating borane-amines with trifluoroacetic acid, have been shown to be efficient reagents for a one-pot, tandem reductive amination/alkylation-cycloamidation of keto or amino acids to achieve the synthesis of 5-aryl or 5-methyl pyrrolidin-2-ones and 6-aryl or 6-methyl piperidin-2-ones.
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Affiliation(s)
| | - Shivani Choudhary
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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4
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Chowdhury D, Mukherjee A. Easy Access to Tertiary Amines from Carbonyl Compounds with Substituted Amine-Boranes: A Substrate, Catalyst, and Additive-Free Approach Under Mild Conditions. Chem Asian J 2023; 18:e202300661. [PMID: 37671911 DOI: 10.1002/asia.202300661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 09/07/2023]
Abstract
Tertiary amines are ubiquitous and play an essential role in organocatalysis, pharmaceuticals, and fine chemicals. Amongst various synthetic procedures known for their synthesis, the reductive amination of carbonyl compounds has been found to be a proficient method. Over the past few decades, different synthetic strategies for reductive amination have been developed. Most of them suffer from the use of transition metals and/or harsh reaction conditions. Herein, we present an efficient, operationally simple protocol for the chemoselective transformation of carbonyl compounds to tertiary amines under benign conditions. The strategy encompasses a broad substrate scope under the metal-free condition at room temperature and does not require any solvent. A detailed mechanistic investigation was performed with the aid of control experiments and computational study to shed light on the reaction pathway.
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Affiliation(s)
- Deep Chowdhury
- Department of Chemistry, Indian Institute of Technology Bhilai, GEC Campus, Sejbahar, Raipur-492015, Chhattisgarh, India
| | - Arup Mukherjee
- Department of Chemistry, Indian Institute of Technology Bhilai, GEC Campus, Sejbahar, Raipur-492015, Chhattisgarh, India
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5
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Ramachandran PV, Alawaed AA, Singh A. Titanium-Mediated Reduction of Carboxamides to Amines with Borane-Ammonia. Molecules 2023; 28:4575. [PMID: 37375131 DOI: 10.3390/molecules28124575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
In this study, the successful titanium tetrachloride-catalyzed reduction of aldehydes, ketones, carboxylic acids, and nitriles with borane-ammonia was extended to the reduction (deoxygenation) of a variety of aromatic and aliphatic pri-, sec- and tert-carboxamides, by changing the stoichiometry of the catalyst and reductant. The corresponding amines were isolated in good to excellent yields, following a simple acid-base workup.
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Affiliation(s)
| | - Abdulkhaliq A Alawaed
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Aman Singh
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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6
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Rajendran N, Kamaraj K, Janakiraman S, Saral M, Dixneuf PH, Bheeter CB. A sustainable metal and base-free direct amidation of esters using water as a green solvent. RSC Adv 2023; 13:14958-14962. [PMID: 37200700 PMCID: PMC10186333 DOI: 10.1039/d3ra02637j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 04/28/2023] [Indexed: 05/20/2023] Open
Abstract
Herein, we report a simple and efficient synthetic approach for direct amidation of esters via C(acyl)-O bond cleavage without any additional reagents or catalysts, using only water as a green solvent. Subsequently, the reaction byproduct is recovered and utilized for the next phase of ester synthesis. This method emphasized metal-free, additive-free, and base-free characteristics making it a new, sustainable, and eco-friendly way to realize direct amide bond formation. In addition, the synthesis of the drug molecule diethyltoluamide and the Gram-scale synthesis of a representative amide are demonstrated.
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Affiliation(s)
- Nanthini Rajendran
- Department of Chemistry, School of Advanced Sciences, Vellore of Institute of Technology Vellore-632014 TamilNadu India
| | - Kiruthigadevi Kamaraj
- Department of Chemistry, School of Advanced Sciences, Vellore of Institute of Technology Vellore-632014 TamilNadu India
| | - Saranya Janakiraman
- Department of Chemistry, School of Advanced Sciences, Vellore of Institute of Technology Vellore-632014 TamilNadu India
| | - Mary Saral
- Department of Chemistry, School of Advanced Sciences, Vellore of Institute of Technology Vellore-632014 TamilNadu India
| | | | - Charles Beromeo Bheeter
- Department of Chemistry, School of Advanced Sciences, Vellore of Institute of Technology Vellore-632014 TamilNadu India
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7
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Ramachandran PV, Hamann HJ. Dehydroborylation of Terminal Alkynes Using Lithium Aminoborohydrides. Molecules 2023; 28:molecules28083433. [PMID: 37110669 PMCID: PMC10144115 DOI: 10.3390/molecules28083433] [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: 03/22/2023] [Revised: 04/10/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Dehydrogenative borylation of terminal alkynes has recently emerged as an atom-economical one-step alternative to traditional alkyne borylation methodologies. Using lithium aminoborohydrides, formed in situ from the corresponding amine-boranes and n-butyllithium, a variety of aromatic and aliphatic terminal alkyne substrates were successfully borylated in high yield. The potential to form mono-, di-, and tri-B-alkynylated products has been shown, though the mono-product is primarily generated using the presented condition. The reaction has been demonstrated at large (up to 50 mmol) scale, and the products are stable to column chromatography as well as acidic and basic aqueous conditions. Alternately, the dehydroborylation can be achieved by treating alkynyllithiums with amine-boranes. In that respect, aldehydes can act as starting materials by conversion to the 1,1-dibromoolefin and in situ rearrangement to the lithium acetylide.
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Affiliation(s)
- P Veeraraghavan Ramachandran
- Herbert C. Brown Center for Borane Research, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Henry J Hamann
- Herbert C. Brown Center for Borane Research, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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8
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A new facet of amide synthesis by tandem acceptorless dehydrogenation of amines and oxygen transfer of DMSO. J Catal 2023. [DOI: 10.1016/j.jcat.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Ramachandran PV, Alawaed AA, Hamann HJ. A Safer Reduction of Carboxylic Acids with Titanium Catalysis. Org Lett 2022; 24:8481-8486. [PMID: 36377825 DOI: 10.1021/acs.orglett.2c03326] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ammonia-borane, shown previously to react with carboxylic acids under reflux to form primary amides, reduces acids to alcohols at room temperature in the presence of catalytic TiCl4. The process, which is tolerant of a variety of potentially reactive functional groups, including N-protected amino acids, can be employed for the selective reduction of acids in the presence of amides, nitriles and, to some extent, esters. Aliphatic acids can be selectively reduced in the presence of aromatic acids.
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Affiliation(s)
| | - Abdulkhaliq A Alawaed
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Henry J Hamann
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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10
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Ramachandran PV, Alawaed AA, Hamann HJ. TiCl 4-Catalyzed Hydroboration of Ketones with Ammonia Borane. J Org Chem 2022; 87:13259-13269. [PMID: 36094411 DOI: 10.1021/acs.joc.2c01744] [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
Investigation of a variety of Lewis acids for the hydroboration-hydrolysis (reduction) of ketones with amine-boranes has revealed that catalytic (10 mol %) titanium tetrachloride (TiCl4) in diethyl ether at room temperature immensely accelerates the reaction of ammonia borane. The product alcohols are produced in good to excellent yields within 30 min, even with ketones which typically requires 24 h or longer to reduce under uncatalyzed conditions. Several potentially reactive functionalities are tolerated, and substituted cycloalkanones are reduced diastereoselectively to the thermodynamic product. A deuterium labeling study and 11B NMR analysis of the reaction have been performed to verify the proposed hydroboration mechanism.
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Affiliation(s)
| | - Abdulkhaliq A Alawaed
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Henry J Hamann
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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11
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Melnykov KP, Tavlui O, Skreminskiy A, Kuchkovska YO, Grygorenko OO. Impact of Fluoroalkyl Substituents on the Physicochemical Properties of Saturated Heterocyclic Amines. Chemistry 2022; 28:e202201601. [DOI: 10.1002/chem.202201601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Kostiantyn P. Melnykov
- Enamine Ltd. Chervonotkatska Street 78 Kyiv 02094 Ukraine
- Taras Shevchenko National University of Kyiv Volodymyrska Street 60 Kyiv 01601 Ukraine
| | - Olha Tavlui
- Enamine Ltd. Chervonotkatska Street 78 Kyiv 02094 Ukraine
- Taras Shevchenko National University of Kyiv Volodymyrska Street 60 Kyiv 01601 Ukraine
| | | | - Yuliya O. Kuchkovska
- Enamine Ltd. Chervonotkatska Street 78 Kyiv 02094 Ukraine
- Current address: Biozentrum University of Basel Spitalstrasse 41 4056 Basel Switzerland
| | - Oleksandr O. Grygorenko
- Enamine Ltd. Chervonotkatska Street 78 Kyiv 02094 Ukraine
- Taras Shevchenko National University of Kyiv Volodymyrska Street 60 Kyiv 01601 Ukraine
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12
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Ramachandran PV, Hamann HJ, Mishra S. Aminoboranes via Tandem Iodination/Dehydroiodination for One-Pot Borylation. ACS OMEGA 2022; 7:14377-14389. [PMID: 35573212 PMCID: PMC9089688 DOI: 10.1021/acsomega.2c01461] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 03/31/2022] [Indexed: 06/15/2023]
Abstract
A rapid synthesis of aminoboranes from amine-boranes utilizing an iodination/dehydroiodination sequence is described. Monomeric aminoboranes are generated exclusively from several substrate adducts, following an E2-type elimination, with the added base playing a critical role in monomer vs dimer formation. Diisopropylaminoborane formed using this methodology has been applied to a one-pot palladium-catalyzed conversion of iodo- and bromoarenes to the corresponding boronates. Additionally, modification of the workup allows for isolation of the boronic acid and recovery of the utilized amine.
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Affiliation(s)
| | - Henry J. Hamann
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United
States
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13
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Györke G, Dancsó A, Volk B, Bezúr L, Hunyadi D, Szalóki I, Milen M. Direct Use of Copper-Containing Minerals in Goldberg Arylation of Amides. Catal Letters 2022. [DOI: 10.1007/s10562-022-03989-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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14
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Braddock DC, Davies JJ, Lickiss PD. Methyltrimethoxysilane (MTM) as a Reagent for Direct Amidation of Carboxylic Acids. Org Lett 2022; 24:1175-1179. [PMID: 35084870 PMCID: PMC9007566 DOI: 10.1021/acs.orglett.1c04265] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
Methyltrimethoxysilane [MTM, CH3Si(OMe)3]
has been demonstrated to be an effective, inexpensive, and safe reagent
for the direct amidation of carboxylic acids with amines. Two simple
workup procedures that provide the pure amide product without the
need for further purification have been developed. The first employs
an aqueous base-mediated annihilation of MTM. The second involves
simple product crystallization from the reaction mixture providing
a low process mass intensity
direct amidation protocol.
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Affiliation(s)
- D Christopher Braddock
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 82 Wood Lane, London W12 0BZ, U.K
| | - Joshua J Davies
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 82 Wood Lane, London W12 0BZ, U.K
| | - Paul D Lickiss
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 82 Wood Lane, London W12 0BZ, U.K
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15
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Zhang Y, de Azambuja F, Parac-Vogt TN. Zirconium oxo clusters as discrete molecular catalysts for the direct amide bond formation. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00421f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A discrete dodecanuclear Zr oxo cluster catalyzed the direct formation of amide bonds without the need of water scavenging or dry reactions conditions showcasing the potential of these molecular clusters to become a new class of efficient catalysts.
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Affiliation(s)
- Yujie Zhang
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
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16
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Song H, Xiao Y, Zhang Z, Xiong W, Wang R, Guo L, Zhou T. Switching Selectivity in Copper-Catalyzed Transfer Hydrogenation of Nitriles to Primary Amine-Boranes and Secondary Amines under Mild Conditions. J Org Chem 2021; 87:790-800. [PMID: 34958575 DOI: 10.1021/acs.joc.1c02413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A simple and efficient copper-catalyzed selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine-BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to 95%. The strategy was applied to the synthesis of 15N labeled in 89% yield.
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Affiliation(s)
- Hao Song
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China
| | - Yao Xiao
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China
| | - Zhuohua Zhang
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China
| | - Wanjin Xiong
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China
| | - Ren Wang
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China.,CNPC Engineering Technology R & D Company Limited, Beijing 102206, PR China
| | - Liangcheng Guo
- Sinopec Jianghan Salt Chemical Hubei Company Limited, Hubei 433121, PR China
| | - Taigang Zhou
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, PR China
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17
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Zheng Y, Liu W, Ren Y, Guo Y, Tian X. Copper‐Catalyzed Cleavage of Aryl C(OH)−C Bonds to Access Aryl Nitriles. ChemistrySelect 2021. [DOI: 10.1002/slct.202103485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yi Zheng
- College of Science Henan Agricultural University Zhengzhou Henan 450002 P.R. China
| | - Wenbo Liu
- College of Science Henan Agricultural University Zhengzhou Henan 450002 P.R. China
| | - Yun‐Lai Ren
- College of Science Henan Agricultural University Zhengzhou Henan 450002 P.R. China
| | - Yinggang Guo
- College of Science Henan Agricultural University Zhengzhou Henan 450002 P.R. China
| | - Xinzhe Tian
- College of Science Henan Agricultural University Zhengzhou Henan 450002 P.R. China
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18
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Ramachandran PV, Hamann HJ. Ammonia-borane as a Catalyst for the Direct Amidation of Carboxylic Acids. Org Lett 2021; 23:2938-2942. [PMID: 33826344 DOI: 10.1021/acs.orglett.1c00591] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylic acids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification but is not amenable for esterification. The latter feature has been exploited to prepare hydroxyl- and thiol-containing amides.
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Affiliation(s)
- P Veeraraghavan Ramachandran
- Herbert C. Brown Center for Borane Research, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Henry J Hamann
- Herbert C. Brown Center for Borane Research, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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19
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Govindan K, Lin WY. Ring Opening/Site Selective Cleavage in N-Acyl Glutarimide to Synthesize Primary Amides. Org Lett 2021; 23:1600-1605. [PMID: 33570960 DOI: 10.1021/acs.orglett.1c00010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A LiOH-promoted hydrolysis selective C-N cleavage of twisted N-acyl glutarimide for the synthesis of primary amides under mild conditions has been developed. The reaction is triggered by a ring opening of glutarimide followed by C-N cleavage to afford primary amides using 2 equiv of LiOH as the base at room temperature. The efficacy of the reactions was considered and administrated for various aryl and alkyl substituents in good yield with high selectivity. Moreover, gram-scale synthesis of primary amides using a continuous flow method was achieved. It is noted that our new methodology can apply under both batch and flow conditions for synthetic and industrial applications.
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Affiliation(s)
- Karthick Govindan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC
| | - Wei-Yu Lin
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan, ROC.,Drug Development and Value Creation Research Centre, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC
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