Asymmetric α-Amination of Aldehydes Catalyzed by PS-Diphenylprolinol Silyl Ethers: Remediation of Catalyst Deactivation for Continuous Flow Operation

Polystyrene (PS)-supported diphenylprolinol silyl ethers have been developed as highly active catalysts for the enantioselective a-amination of aldehydes. Understanding the mechanism of catalyst deactivation has led to the development of reaction conditions notably extending catalyst life in repeated recycling (10 cycles; accumulated TON of 480) and has allowed the implementation of a continuous flow alpha-amination process (6 min residence time, 8 h operation).