Process for the preparation of cyclopropane derivatives, intermediates in the synthesis of pyrethroid insecticides

摘要

Compounds of formula:wherein both groups X are chlorine, bromine or trifluoromethyl, or one X is chlorine or bromine and the other is trifluoromethyl, and Y is -CN or -COOR in which R is an alkyl group, are obtained by (A) reacting a compound of the formula:wherein X¹ is chlorine or bromine, with a compound of the formula:in the presence of metallic copper or at least one copper salt I and a base, or (B) reacting a compound of the formula:with a compound of the formula:and chlorine or bromine, in the presence of at least one reducible copper salt and a base, or (C) reacting a compound of formula:with a compound of the formula:wherein X¹ is chlorine or bromine, in the presence of at least one copper salt.