BAKERS-YEAST MEDIATED REDUCTION OF AROMATIC RING-SUBSTITUTED 2-TETRALONES

2-Tetralones mono- and disubstituted with methoxy or hydroxy groups in the aromatic ring are hydrogenated to 2-tetralols in good yields by non-fermenting baker's yeast. The prevalent enantioform of the reduction product and its e.e. were found to depend on the substitution pattern. In one case, i.e, the biotransformation of 5-methoxy-2-tetralone into the corresponding 2-tetralol, an e.e. greater than or equal to 98% was observed. A simple abstract model for explaining and predicting the stereochemical outcome in the yeast-mediated carbonyl reduction of 2-tetralones is proposed.