Bioreduction of aromatic ketones: preparation of chiral benzyl alcohols in both enantiomeric forms

Substituted phenacyl chlorides are reduced with whole-cell biocatalysts to give (R)- or (S)-chlorohydrines in high yields and to make them good for high enantiomeric excess. Yields and enantiomeric purity of the S-enantiomer could be increased by performing bioreduction in the presence of polymeric absorbing resins. With this methodology, 2-chloro-1(S)-(3,4-dichloro-phenyl)-ethanol of 98% e.e. and 2-(R)-(4-nitro-phenyl)-ethanol of 92% e.e. have been prepared and used respectively as precursors in the synthesis of (+)-cis-1(S),4(S)-sertraline and of the β-blocker (R)-nifenalol®.