Enzyme-catalyzed asymmetric synthesis of optically active (R)- and (S)-ethyl -4-phenyl-4-hydroxybutyrate with microbial cells

Abstract

In efforts to obtain carbonyl reductases with high activity and enantioselectivity, forty microorganisms belonging to different taxonomical groups were investigated for the ability to catalyze the enantioselective reduction of ethyl 4-phenyl- 4-oxobutyrate (EPOB) to the corresponding optically active ethyl 4-phenyl-4-hydroxybutyrate (EPHB). Highly enantioselective reduction of EPOB was achieved with Candida magnoliae CGMCC 2.1919 and Saccharomyces cerevisiae CGMCC 2.399 giving the corresponding (R)-EPHB and (S)-EPHB in 99% ee, respectively. The highly enantioselective bioreductions provide simple routes to optically active γ-hydroxyl acid esters that are useful pharmaceutical intermediates and versatile chiral building blocks.