采用锌铜齐-二碘甲烷试剂合成2,2-二甲基环丙烷甲酸甲酯

The synthesis of 2,2-dimethyl cyclopropanecarboxylate by Zn(Cu) -diiodomethane

2,2二甲基环丙烷甲酸甲酯是重要的医药中间体。以异戊烯酸为原料,经酯化、烯键的环丙烷化两步反应得到2,2-二甲基环丙烷甲酯。采用锌铜齐-二碘甲烷作环丙烷化试剂,通过单因素选优法得到最佳反应条件为:n(异戊烯酸甲酯)∶n(二碘甲烷)∶n(锌铜齐Ⅲ)=1∶3.0∶3.0;混合溶剂为V(二氯甲烷)∶V(无水乙醚)=6∶1;回流温度下反应9h。在此条件下,2,2-二甲基环丙烷甲酯的收率达到84.6%。此路线步骤简单、成本较低、收率较高。

2,2-dimethyl cyclopropanecarboxylate is an important intermediate of medicine,which was prepared via esterification,cyclopropanation using 2-methylbutenoic acid as starting material.Using zinc/copper as catalyst,the cyclopropanation proceeded easily with diiodomethane.Some factors which effect the reaction were also discussed,and the proper conditions were given as follows：n（methyl 3-methyl-2-butenoate）：n（diiodomethane）： n（Zn-CuⅢ）=1：3.0：3.0,the solvent is V（methylene dichloride）：V（absolute ethyl ether） =6：1,and the reaction time is 9 hours under reflux temperature.Under the optimic conditions,the yield of 2,2-dimethyl cyclopropanecarboxylate is 84.6%.This route has advantages such as simple procedure,higher yield and lower cost.