University Chemistry ›› 2022, Vol. 37 ›› Issue (5): 2111009.doi: 10.3866/PKU.DXHX202111009

Special Issue: 第2届全国大学生化学实验创新设计竞赛

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Catalytic Asymmetric Synthesis of Chiral α-Amino Ketones

Wei Wen, Chaoxing Li, Fangxiu Ye, Jingfeng Li, Qixiang Guo()   

  • Received:2021-11-02 Accepted:2021-11-04 Published:2022-03-25
  • Contact: Qixiang Guo E-mail:qxguo@swu.edu.cn

Abstract:

Enantiomerism, which is a fundamental concept in organic chemistry, is challenging for many undergraduate students. In current laboratory teaching books, asymmetric syntheses are very limited. Particularly, there are few experimental cases for the synthesis of enantiomers via asymmetric catalysis. We rationally designed a comprehensive experiment for the asymmetric catalysis based on a scientific report for use in teaching chemistry experiments. An optically active α-amino ketone is prepared using a chiral Brønsted-acid-catalyzed three-component asymmetric reductive amination reaction of aniline, 2, 3-butanedione, and benzothiazoline. To emphasize the influence of catalysts on the enantioselectivity of product, chiral Brønsted acids with different configurations and steric groups are introduced as catalysts. The target chiral products will then be analyzed using NMR, chiral HPLC, and polarimetry. This experiment effectively upgrades the current popular two-component, achiral synthesis to a multi-component, chiral synthesis. Results indicate that this experiment has good repeatability, is sufficiently challenging, and promotes exploration and innovation. Implementation of this project will benefit students in learning how to manipulate a multi-component reaction, further understand complicated reaction mechanisms, investigate the factors which influence stereoselectivity, and learn how to carry out an innovative experiment.

Key words: Asymmetric catalysis, Enantiomers, Reductive amination, α-Aminoketones, Multi-component reaction

MSC2000: 

  • G64