【摘要】 以 4 氯乙酰乙酸乙酯为 β 羰基酯的模型底物 ,对面包酵母催化其不对称还原反应立体选择性的控制进行了研究 .实验发现 ,利用诸如烯丙基醇和烯丙基溴等酶抑制剂对面包酵母进行预处理 ,可以控制反应的立体选择性 .用烯丙基醇预处理面包酵母时可以提高S型产物的立体选择性 ;用烯丙基溴预处理时 ,可以使反应的立体选择性从通常的S型产物转变为R型产物 .立体选择性随着预处理时抑制剂浓度的增大和处理时间的延长而提高 .合适的预处理条件可使S型和R型产物的ee值分别达到 95 %和 98% .更多还原

【Abstract】 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.更多还原