Asymmetric synthesis of amino acids via the catalytic reduction of substituted acylaminoacrylic acid azlactones

Abstract

The kinetics of aminolysis and racemization of 2-methyl-4-benzyloxazolin-5-one upon reaction with S-phenylalanine methyl ester have been studied in dimethoxyethane solvent. The rates of aminolysis and racemization are comparable. Addition of an achiral component, namely Et3N, to the reaction mixture, however, dramatically increases the rate of racemization. The presence of Et3N also increases the ratio of rate constants for the formation of RS- and SS-diastereomers, which determines the reaction stereoselectivity.