Process for the preparation of unsaturated alpha-chlorinated compounds of two electroattractive groups in the beta position

摘要

Compounds of formula IMAGE (Ia) or IMAGE (Ib) in which n denotes an integer from 1 to 10 and X and Y, which are identical or different, each denote an electron-attracting group, are made by reacting a halogenating agent with a compound of formula IMAGE (IIa) or IMAGE (IIb) in which R, X and Y are as hereinbefore defined, anionized by a base.