SELF-CONDENSATION OF p-CHLOROPHENACYL CHLORIDE IN THE PRESENCE OF GRIGNARD REAGENT

Abstract

A crystalline by-product, formed in the reaction of p-chlorophenacyl chloride (I) with ethylmagnesium chloride, has been identified as 1,3-dichloro-2,4-bis(p-chlorophenyl)-2,4-hexanediol (IV). Its formation has been attributed to aldolization of I followed by reaction with Grignard reagent at the carbonyl function. The dehydrochlorination of IV yielded one of two possible compounds to which the diepoxide structure VI was assigned on the basis of n.m.r. spectra. The dehydrochlorinated product (VI) was synthesized from 1-chloro-2,3-epoxy-2,4-bis(p-chlorophenyl)-4-butanone (VIII) by treatment with ethylmagnesium chloride followed by reaction of the resulting epoxy alcohol IX with alcoholic alkali. It is suggested that the epoxy alcohol IX did not dehydrochlorinate directly to the 3,4-epoxytetrahydrofuran derivative V but instead rearranged first by epoxide alcohol transposition to X and then dehydrochlorinated to 1,2,3,4-diepoxy-2,4-bis(p-chlorophenyl)hexane (VI).