Deracemization of 1-phenylethanol via tandem biocatalytic oxidation and reduction

Abstract ( R )-1-Arylethanols and other secondary alcohols were prepared at high ee (>90%) by oxidative kinetic resolution using resting cells of the yeast Candida albicans CCT 0776. The deracemization process of 1-phenylethanol 1a catalyzed by the yeast was elucidated by studying each step separately. It was determined that the reaction occurred via cyclic deracemization, to give ( R )- 1a in 89% yield and with 98% ee . Finally, deracemization by stereoinversion of rac - 1a was studied using a tandem process of C. albicans followed by Lactobacillus brevis CCT 3745. Inverting the sequence of these microorganisms produced an enantiomerically pure antipode.