Allylic Rearrangements. XXVI. The Reaction of Butenyl Mesitoates and Chlorides with Phenylmagnesium Bromide

Abstract

In 1941, Arnold, Bank and Liggett suggested that the formation of allylbenzene from the reaction of allyl mesitoate with phenylmagnesium bromide involved the combination of an intermediate allyl carbonium ion with a phenyl carbanion from the Grignard reagent. In a later paper this mechanism was modified since it was found that the reaction of crotyl mesitoate with phenylmagnesium bromide gave only crotylbenzene instead of the mixture of crotyl- and α-methylallylbenzenes expected from an intermediate butenyl carbonium ion. The exclusive formation of crotylbenzene was formulated as being the result of a concerted process involving a cyclic intermediate.

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