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Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
Enantioselectivity switch in asymmetric Michael addition reactions using phosphonium salts
Guosheng Fang1, Hongyu Wang2, Changwu Zheng2
1Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China. zhaog@mail.sioc.ac.cn.
Abstract:
Efficient access to two enantiomers of one chiral compound is critical for the discovery of drugs. However, it is still a challenging problem owing to the difficulty in obtaining two enantiomers of one chiral catalyst. Here, we report a general method to obtain both enantiomeric products via fine tuning the hydrogen-bonding interactions of phosphonium salts. Amino acid derived phosphonium salts and dipeptide derived phosphonium salts exhibited different properties for controlling the transition state, which could efficiently promote the Michael addition reaction to give opposite configurations of products with high yields and enantioselectivities. Preliminary investigations on the mechanism of the reaction and applications of the products were also performed.
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