Stereoselective enone reductions by Saccharomyces carlsbergensis old yellow enzyme

A series of 2- and 3-alkyl-substituted 2-cyclohexenones were shown to be substrates for the old yellow enzyme of Saccharomyces carlsbergensis expressed in Escherichia coli cells. Chemo- and stereoselective alkene reductions were observed, and the absolute configurations of the products could be predicted from the X-ray crystal structure of the protein. No competing carbonyl reductions were detected. These results support the notion that enzymes of this family may be useful in stereoselective organic synthesis.