Volume 63, Issue 14 e202319662
Research Article

Rhodium-Catalyzed Asymmetric Hydrogenation and Transfer Hydrogenation of 1,3-Dipolar Nitrones

Liren Xu

Liren Xu

Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China

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Tilong Yang

Tilong Yang

Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China

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Hao Sun

Hao Sun

Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China

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Jingwen Zeng

Jingwen Zeng

Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China

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Shuo Mu

Shuo Mu

Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China

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Prof. Xumu Zhang

Prof. Xumu Zhang

Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China

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Prof. Gen-Qiang Chen

Corresponding Author

Prof. Gen-Qiang Chen

Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China

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First published: 17 February 2024
Citations: 16

Graphical Abstract

The enantioselective reduction of 1,3-dipolar nitrones to hydroxylamines was achieved by Rh(III)-catalyzed asymmetric hydrogenation and transfer hydrogenation. A wide range of chiral N,N-disubstituted hydroxylamines were synthesized with up to 99 % yield and >99 % ee. Mechanistic investigations and DFT calculations were conducted to elucidate the origin of reactivity and enantioselectivity.

Abstract

Owing to their distinctive 1,3-dipolar structure, the catalytic asymmetric hydrogenation of nitrones to hydroxylamines has been a formidable and longstanding challenge, characterized by intricate enantiocontrol and susceptibility to N−O bond cleavage. In this study, the asymmetric hydrogenation and transfer hydrogenation of nitrones were accomplished with a tethered TsDPEN-derived cyclopentadienyl rhodium(III) catalyst (TsDPEN: p-toluenesulfonyl-1,2-diphenylethylene-1,2-diamine), the reaction proceeds via a novel 7-membered cyclic transition state, producing chiral hydroxylamines with up to 99 % yield and >99 % ee. The practical viability of this methodology was underscored by gram-scale catalytic reactions and subsequent transformations. Furthermore, mechanistic investigations and DFT calculations were also conducted to elucidate the origin of enantioselectivity.

Conflict of interests

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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