3-Halogenoethyl- or propyl-2,2-dimethylcyclopropane carboxylic acid esters, which are intermediates in the preparation of synthetic pyrethroids, are prepared by the reaction of certain halogenopentenes or hexenes with a diazoacetic ester in the presence of a catalyst which is metallic copper or a copper (II) salt, a rhodium (II) salt of a carboxylic acid or a transition metal complex of certain chiral Schiff bases. By the use of the latter class of catalysts the yield of preferred cis IR isomer may be increased relative to the other possible isomers.
3-卤代乙基-或丙基-2,2-二
甲基环丙烷羧酸酯是制备合成拟
除虫菊酯的中间体,其制备方法是某些卤代
戊烯或己烯与
重氮乙酸酯在
金属
铜或
铜(II)盐、
羧酸铑(II)盐或某些手性席夫碱的过渡
金属络合物催化剂存在下进行反应。与其他可能的异构体相比,使用后一类催化剂可以提高优选顺式红外异构体的产率。