Green Asymmetric Reduction of Methylacetophenone

Abstract— We studied the possibility of synthesizing optically pure (S)-(–)-1-(4-methylphenyl)ethanol from the corresponding 1-(4-methylphenyl)ethanone catalyzed by D. carotа cells. The effect of exogenous reducing agents on the enantioselectivity of the reduction and the yield of the product was studied. We found conditions that make it possible to obtain (S)-(–)-1-(4-methylphenyl)ethanol by biotransformation of 1-(4-methylphenyl)ethanone catalyzed by D. carota cells for 144 h with 98% yield (76% ee). Bioreduction of the initial 1-(4-methylphenyl)ethanone in the presence of 4% ethanol leads to a decrease in the yield of (S)-(–)-1-(4-methylphenyl)ethanol to 60%, but the optical purity reaches 98% ee. Transformation of 1-(4-methylphenyl)ethanone in the presence of glucose leads to the formation of (S)-(–)-1-(4-methylphenyl)ethanol in 76% yield, while the enantiomeric excess increases to 96% ee.