Regio- and Enantio-selective Reduction ofα,γ-Diketones by Fermenting Bakers’ Yeast

Abstract
Reduction of various numbers of 2,4-alkanediones by fermenting bakers’ yeast has been found to be highly regio- and enantio selective, resulting in the formation of 2-hydroxy-4-alkanones. In some cases, optical purities of the products exceeded over 99% as determined by HPLC analysis of MTPA esters. The highest yield was obtained when the reaction was carried out at,pH 8 with low substrate concentration. As the representative β-hydroxyketones, the absolute configuration of ( + )-2-hydroxy-4-octanone (2d) and ( + )-3-hydroxy-1-phenyl-1-butanone (2h) was unambiguously determined to be (S) by comparing the specific rotation of diol derivatives with those of authentic specimens.