Volume 134, Issue 46 e202212948
Forschungsartikel

Cooperative Catalyst-Enabled Regio- and Stereodivergent Synthesis of α-Quaternary α-Amino Acids via Asymmetric Allylic Alkylation of Aldimine Esters with Racemic Allylic Alcohols

Lu Xiao

Lu Xiao

College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072 China

State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Shanghai, 230021 China

These authors contributed equally to this work.

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Xin Chang

Xin Chang

College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072 China

These authors contributed equally to this work.

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Hui Xu

Hui Xu

Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, Tianjin, 300072 China

These authors contributed equally to this work.

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Qi Xiong

Qi Xiong

College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072 China

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Prof. Dr. Yanfeng Dang

Corresponding Author

Prof. Dr. Yanfeng Dang

Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, Tianjin, 300072 China

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Prof. Dr. Chun-Jiang Wang

Corresponding Author

Prof. Dr. Chun-Jiang Wang

College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072 China

State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Shanghai, 230021 China

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Dedicated to the 60th anniversary of Institute of Elemento-Organic Chemistry at Nankai University
First published: 26 September 2022

Abstract

We describe cooperative bimetallic catalysis that enables regio-/stereodivergent asymmetric α-allylations of aldimine esters. By employing Et3B as the key activator, racemic allylic alcohols can be directly ionized to form Pd or Ir-π-allyl species in the presence of achiral Pd or chiral Ir complexes, respectively. The less or more substituted allylic termini of the metal-π-allyl species are amenable to nucleophilic attack by the chiral Cu-azomethine ylide, the formation of which is simultaneously facilitated by Et3B, affording α-quaternary α-amino acids with high regioselectivity and excellent stereoselectivity. The use of readily available allylic alcohols as electrophilic precursors represents an improvement from an environmental and atom/step economy perspective. Computational mechanistic studies reveal the crucial role of the Et3B additive and the origins of stereo- and regioselectivities by analyzing steric effects, dispersion interactions, and frontier orbital population.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

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