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Li J, Gong S, Gao S, Chen J, Chen WW, Zhao B. Asymmetric α-C(sp 3)-H allylic alkylation of primary alkylamines by synergistic Ir/ketone catalysis. Nat Commun 2024; 15:939. [PMID: 38296941 PMCID: PMC10830461 DOI: 10.1038/s41467-024-45131-3] [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: 10/05/2023] [Accepted: 01/12/2024] [Indexed: 02/02/2024] Open
Abstract
Primary alkyl amines are highly reactive in N-nucleophilic reactions with electrophiles. However, their α-C-H bonds are unreactive towards electrophiles due to their extremely low acidity (pKa ~57). Nonetheless, 1,8-diazafluoren-9-one (DFO) can activate primary alkyl amines by increasing the acidity of the α-amino C-H bonds by up to 1044 times. This makes the α-amino C-H bonds acidic enough to be deprotonated under mild conditions. By combining DFO with an iridium catalyst, direct asymmetric α-C-H alkylation of NH2-unprotected primary alkyl amines with allylic carbonates has been achieved. This reaction produces a wide range of chiral homoallylic amines with high enantiopurities. The approach has successfully switched the reactivity between primary alkyl amines and allylic carbonates from intrinsic allylic amination to the α-C-H alkylation, enabling the construction of pharmaceutically significant chiral homoallylic amines from readily available primary alkyl amines in a single step.
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Affiliation(s)
- Jianyu Li
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Frontiers Science Center of Biomimetic Catalysis and Shanghai Normal University, Shanghai, 200234, China
| | - Sheng Gong
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Frontiers Science Center of Biomimetic Catalysis and Shanghai Normal University, Shanghai, 200234, China
| | - Shaolun Gao
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Frontiers Science Center of Biomimetic Catalysis and Shanghai Normal University, Shanghai, 200234, China
| | - Jianfeng Chen
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Frontiers Science Center of Biomimetic Catalysis and Shanghai Normal University, Shanghai, 200234, China.
| | - Wen-Wen Chen
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Frontiers Science Center of Biomimetic Catalysis and Shanghai Normal University, Shanghai, 200234, China
| | - Baoguo Zhao
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Frontiers Science Center of Biomimetic Catalysis and Shanghai Normal University, Shanghai, 200234, China.
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Liu L, Luo R, Tong J, Liao J. Iridium-catalysed reductive allylic amination of α,β-unsaturated aldehydes. Org Biomol Chem 2024; 22:585-589. [PMID: 38131265 DOI: 10.1039/d3ob01753b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Allylic amination is a powerful tool for constructing N-allylic amines widely found in bioactive molecules. Generally, allylic alcohols and unsaturated hydrocarbons have been considered for allylic amination reactions to minimize waste production. Herein, we present an iridium-catalysed method for reductive allylic amination of α,β-unsaturated aldehydes with amines to afford N-allylic amines under air conditions. This protocol is demonstrated to provide products from many substrates (41 examples) in moderate-to-excellent yields. This synthetic methodology is also highlighted by the synthesis of drug molecules, optically pure products, as well as scale-up experiments.
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Affiliation(s)
- Liang Liu
- School of Pharmacy, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, P. R. China.
| | - Renshi Luo
- College of Chemistry and Environmental Engineering, Shaoguan University, Shaoguan, 512005, Guangdong Province, P. R. China
| | - Jinghui Tong
- School of Pharmacy, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, P. R. China.
| | - Jianhua Liao
- School of Pharmacy, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, P. R. China.
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Aleku GA, Titchiner GR, Roberts GW, Derrington SR, Marshall JR, Hollfelder F, Turner NJ, Leys D. Enzymatic N-Allylation of Primary and Secondary Amines Using Renewable Cinnamic Acids Enabled by Bacterial Reductive Aminases. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2022; 10:6794-6806. [PMID: 35634269 PMCID: PMC9131517 DOI: 10.1021/acssuschemeng.2c01180] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/25/2022] [Indexed: 06/15/2023]
Abstract
Allylic amines are a versatile class of synthetic precursors of many valuable nitrogen-containing organic compounds, including pharmaceuticals. Enzymatic allylic amination methods provide a sustainable route to these compounds but are often restricted to allylic primary amines. We report a biocatalytic system for the reductive N-allylation of primary and secondary amines, using biomass-derivable cinnamic acids. The two-step one-pot system comprises an initial carboxylate reduction step catalyzed by a carboxylic acid reductase to generate the corresponding α,β-unsaturated aldehyde in situ. This is followed by reductive amination of the aldehyde catalyzed by a bacterial reductive aminase pIR23 or BacRedAm to yield the corresponding allylic amine. We exploited pIR23, a prototype bacterial reductive aminase, self-sufficient in catalyzing formal reductive amination of α,β-unsaturated aldehydes with various amines, generating a broad range of secondary and tertiary amines accessed in up to 94% conversion under mild reaction conditions. Analysis of products isolated from preparative reactions demonstrated that only selective hydrogenation of the C=N bond had occurred, preserving the adjacent alkene moiety. This process represents an environmentally benign and sustainable approach for the synthesis of secondary and tertiary allylic amine frameworks, using renewable allylating reagents and avoiding harsh reaction conditions. The selectivity of the system ensures that bis-allylation of the alkylamines and (over)reduction of the alkene moiety are avoided.
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Affiliation(s)
- Godwin A. Aleku
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K.
| | - Gabriel R. Titchiner
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - George W. Roberts
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Sasha R. Derrington
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - James R. Marshall
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Florian Hollfelder
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K.
| | - Nicholas J. Turner
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - David Leys
- Manchester
Institute of Biotechnology, Department of Chemistry, University of Manchester, Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
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