Cyclic or acyclic α-alkyl-α-hydroxy-β-keto esters were reduced by baker’s yeast with high stereospecificity. In the former case, one enantiomer of the racemic mixture was transformed into optically active trans-dihydroxy compounds, while the remaining α-hydroxy-β-keto ester was enantiopure.
                                    环状酵母或无环α-烷基-α-羟基-β-
酮酸酯被具有高立体特异性的面包酵母还原。在前一种情况下,外消旋混合物的一种对映异构体被转化为旋光的反式-二羟基化合物,而其余的α-羟基-β-
酮酸酯是对映体纯的。