Highly enantioselective deracemization of 1-phenyl-1,2-ethanediol and its derivatives by stereoinversion using Candida albicans in a one-pot process

Abstract

A very simple methodology was developed to transform racemic 1-(4-substitutedphenyl)-1,2-ethanediols using resting cells of Candida albicans CCT 0776 through a one-pot two-step process in which the (R)-stereoisomer was completely oxidized to the corresponding substituted-α-hydroxyacetophenones, which were completely reduced to produce (S)-1-(4-substitutedphenyl)-1,2-ethanediols in good isolated yield (60–85%) and with high enantiomeric excess (99% ee). The overall process corresponded to an enantioselective deracemization by stereoinversion of the (R)-enantiomer. The process was not achieved for other similar 1,2-diols using the same reaction conditions, which indicates a structural restriction of substrates by the active pocket of the enzymes of C. albicans involved in the stereoinversion process.