Conversion of esters (R.sup.1)(R.sup.2)C(C Hal.sub.3)OX, X being-P Hal.sub.2, --C(O)OR.sup.3 or ##STR1## R.sup.1, R.sup.3 and R.sup.4 being optionally substituted hydrocarbyl groups and R.sup.2 methyl or hydrogen, with zinc in acetic acid gives a very high yield of a dihalovinyl compound (R.sup.1)(R.sup.2)C.dbd.C Hal.sub.2, e.g., of the ethyl ester of the parent acid of pyrethroid insecticides.
酯的转化(R.sup.1)(R.sup.2)C(C Hal.sub.3)OX,其中X为-P Hal.sub.2,--C(O)OR.sup.3或##STR1## R.sup.1,R.sup.3和R.sup.4是可选取代的烃基基团,R.sup.2是甲基或氢,在
乙酸锌的作用下,可得到非常高收率的二卤
乙烯化合物(R.sup.1)(R.sup.2)C.dbd.C Hal.sub.2,例如拟
除虫菊酯类杀虫剂的母酸
乙酯。