Asymmetric Reduction of Ethyl 2-methyl 3-oxobutanoate by Fungi

Abstract

  Seven fungi, which are found to reduce ethyl 3-oxobutanoate in high yields, were tested for their reducing ability for ethyl 2-methyl 3-oxobutanoate. We obtained some interesting findings. In particular, Penicillium purpurogenum reduced ethyl 2-methyl 3-oxobutanoate to the corresponding alcohols with the diastereomer (anti/syn) ratio of 93/7 with the enantiomeric excess of anti-(2S, 3S)- and syn-(2S, 3R)-hydroxy esters of 90 and >99 ee%, respectively.