Biocatalytic ways to optically active 2-amino-1-phenylethanols

Abstract

Optically active building blocks of 2-amino-1-ethanols, such as 2-amino-, 2-halo-and 2-azido-1-phenylethanols, 2-hydroxy carboxylic acid derivatives and aryl cyanohydrins, can be conveniently prepared by biocatalytic ways. Systems that do not need added cofactors are described. Whole cell catalysis is economical for asymmetric synthesis Oxynitrilases produce (R)- and (S)-aryl cyanohydrins with high enantiomeric purities (in most cases ee>90%) and chemical yields (usually over 80%). Baker's yeast preferentially works pro-(R)-selectively on ketones, but the chemical shift is usually far from theoretical. Kinetic resolution by lipases shows the widest spectrum of use. the enantiomeric purity over 95% and the chemical yield close to the theoretical 50% value being usually attained for the enantiomers of a racemic starting material. In situ methods enable the enhancement of the chemical yield of one enantiomer over the 50% limit. © Acta Chemica Scandinavica 1996.