Enantioselective Reduction of 4‐Fluoroacetophenone at High Substrate Concentration using a Tailor‐Made Recombinant Whole‐Cell Catalyst

A practical and highly efficient biocatalytic synthesis of optically active (R)‐4‐fluorophenylethan‐1‐ol has been developed based on reduction of the corresponding 4‐fluoroacetophenone in the presence of a tailor‐made recombinant whole‐cell biocatalyst, containing an alcohol dehydrogenase and a glucose dehydrogenase. The reaction proceeds in a pure aqueous solvent media at a substrate concentration of ca. 0.5 M, and gives the desired product with high conversion (>95 %), good yield (87 %) and with an excellent enantioselectivity of >99 % ee. In addition, activity tests further showed that also the analogous 2‐ and 3‐fluoroacetophenones are promising substrates.