A process for preparing a halogenated ester of formula i

摘要

A process for preparing halogenated compounds of formula RCY(Z)CH2CH(X)C(CH3)CH2COR1 where X, Y and Z are halo, R is alkyl, halo, haloalkyl or aryl, and R1 is hydroxy, halo, alkoxy, alkyl or haloalkyl, or the residue of a pyrethroidal alcohol, in which a compound of formula CH2=CHC(CH3)2COR1 is reacted with a sulphonyl halide of formula RCY(Z)SO2X. The process avoids the use of volatile halocarbons in the production of valuable intermediates for insecticides.