摘要：

Using the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to enantiomeric pure ethyl 4-chloro-3-hydroxybutanoate (CHBE) as the model reaction, the method for controlling the stereoselectivity of reduction of β-oxo esters by pretreatment of the yeast was studied. The primary technique was pretreatment of the yeast cells with enzyme inhibitors, such as allyl alcohol and allyl bromide, for a period before asymmetric transformation of COBE. It was found that the stereoselectivity of the reduction reaction could be controlled to produce S-CHBE when the yeast cells were pretreated with allyl alcohol. The ee of S-CHBE was improved with increasing the concentration of allyl alcohol and the pretreatment time. 95% for ee of S-CHBE could be reached when allyl alcohol was 1 g/L and pretreatment time was 2 h. On the contrary, the pretreatment with allyl bromide could turn the stereoselectivity of this reduction reaction from S-CHBE to R-CHBE. Also the inhibitor concentration and pretreatment time had positive effect on ee of R-CHBE. And the ee of R-CHBE could reach to 98% when an appropriate condition was applied.

展开