A series of ortho-, meta-, and para- halogen-substituted methyl benzoate esters was subjected to enzymatic dihydroxylation via the whole-cell fermentation with E. coli JM109 (pDTG601A). Only ortho-substituted benzoates were metabolized. Methyl 2-fluorobenzoate yielded one diol regioselectively whereas methyl 2-chloro-, methyl 2-bromo- and methyl 2-iodobenzoates each yielded a mixture of regioisomers. Absolute stereochemistry was determined for all new metabolites. Computational analysis of these results and a possible rationale for the regioselectivity of the enzymatic dihydroxylation is advanced.
一系列邻、间和对卤代甲基
苯甲酸酯通过全细胞发酵与大肠杆菌JM109(pDTG601A)发生酶促二羟基化反应。只有邻取代的
苯甲酸酯被代谢。2-
氟苯甲酸甲酯产生一种二醇,而2-
氯、2-
溴和
2-碘苯甲酸甲酯则分别产生一种区域异构体混合物。所有新代谢产物的绝对立体
化学结构均已确定。对这些结果进行了计算分析,并提出了酶促二羟基化反应区域选择性的可能原理。