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Zhao C, Gao R, Ma W, Li M, Li Y, Zhang Q, Guan W, Fu J. A facile synthesis of α,β-unsaturated imines via palladium-catalyzed dehydrogenation. Nat Commun 2024; 15:4329. [PMID: 38773128 PMCID: PMC11109338 DOI: 10.1038/s41467-024-48737-9] [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: 11/30/2023] [Accepted: 05/13/2024] [Indexed: 05/23/2024] Open
Abstract
The dehydrogenation adjacent to an electron-withdrawing group provides an efficient access to α,β-unsaturated compounds that serving as versatile synthons in organic chemistry. However, the α,β-desaturation of aliphatic imines has hitherto proven to be challenging due to easy hydrolysis and preferential dimerization. Herein, by employing a pre-fluorination and palladium-catalyzed dehydrogenation reaction sequence, the abundant simple aliphatic amides are amendable to the rapid construction of complex molecular architectures to produce α,β-unsaturated imines. Mechanistic investigations reveal a Pd(0)/Pd(II) catalytic cycle involving oxidative H-F elimination of N-fluoroamide followed by a smooth α,β-desaturation of the in-situ generated aliphatic imine intermediate. This protocol exhibits excellent functional group tolerance, and even the carbonyl groups are compatible without any competing dehydrogenation, allowing for late-stage functionalization of complex bioactive molecules. The synthetic utility of this transformation has been further demonstrated by a diversity-oriented derivatization and a concise formal synthesis of (±)-alloyohimbane.
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Affiliation(s)
- Chunyang Zhao
- Department of Chemistry, Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis and Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Rongwan Gao
- Department of Chemistry, Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Wenxuan Ma
- Department of Chemistry, Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis and Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Miao Li
- Department of Chemistry, Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis and Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Yifei Li
- Department of Chemistry, Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis and Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Qian Zhang
- Department of Chemistry, Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis and Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Wei Guan
- Department of Chemistry, Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China.
| | - Junkai Fu
- Department of Chemistry, Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis and Institute of Functional Material Chemistry, Northeast Normal University, Changchun, 130024, China.
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Meng G, Hu L, Chan HSS, Qiao JX, Yu JQ. Synthesis of 1,3-Dienes via Ligand-Enabled Sequential Dehydrogenation of Aliphatic Acids. J Am Chem Soc 2023; 145:13003-13007. [PMID: 37285407 PMCID: PMC11139440 DOI: 10.1021/jacs.3c03378] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
1,3-Dienes are common scaffolds in biologically active natural products as well as building blocks for chemical synthesis. Developing efficient methods for the synthesis of diverse 1,3-dienes from simple starting materials is therefore highly desirable. Herein, we report a Pd(II)-catalyzed sequential dehydrogenation reaction of free aliphatic acids via β-methylene C-H activation, which enables one-step synthesis of diverse E,E-1,3-dienes. Free aliphatic acids of varying complexities, including the antiasthmatic drug seratrodast, were found to be compatible with the reported protocol. Considering the high lability of 1,3-dienes and lack of protecting strategies, dehydrogenation of aliphatic acids to reveal 1,3-dienes at the late stage of synthesis offers an appealing strategy for the synthesis of complex molecules containing such motifs.
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Affiliation(s)
| | | | - Hau Sun Sam Chan
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States
| | - Jennifer X. Qiao
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States
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Popova AS, Ogarkova NK, Shapovalov SS, Skabitsky IV, Kultyshkina EK, A.Yakushev I, Vargaftik MN. Synthesis, structure and catalytic properties of Pdii-based bimetallic complexes with ferrocenecarboxylic acid. MENDELEEV COMMUNICATIONS 2022. [DOI: 10.1016/j.mencom.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Keerthana MS, Jeganmohan M. Palladium-Catalyzed Aerobic α,β-Dehydrogenation of Aliphatic Amides. J Org Chem 2022; 87:4873-4882. [PMID: 35319889 DOI: 10.1021/acs.joc.2c00226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A Pd(II)-catalyzed α,β-dehydrogenation of substituted aliphatic amides assisted by a reusable bis-chelating 8-aminoquinoline ligand is demonstrated. Broad spectra of β-substituted including olefin-substituted aliphatic amides are well tolerated. The present protocol efficiently dehydrogenates the less acidic aliphatic amides via the chelation-assisted β-C-H bond activation and replaces the traditional enolate-based strategy.
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Affiliation(s)
| | - Masilamani Jeganmohan
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
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