Optically active ethyl(S)-3-hydroxybutyrate,a useful chiral synthon,was prepared by stereoselective reduction of ethyl acetoacetate of the bread yeast in organic solvent.

• 利用面包酵母在非水相中不对称还原乙酰乙酸乙酯,制备了光学活性的手性化合物S()-3-羟基丁酸乙酯。