Allylic Rearrangements. XVII. The Reactions of Butenylmagnesium Bromide with Active Hydrogen Compounds

Abstract

Previous work has shown that while the butenyl Grignard reagent has a striking tendency to form α-methylallyl derivatives in a wide variety of coupling and carbonyl addition reaction, hydrolysis with dilute sulfuric acid gives a mixture of butenes. It has been demonstrated that the composition of the butene mixture is independent of the ratio of allylic isomers in the starting butenyl halides and that similar butene mixtures are produced using butenylmagnesium chlorides and bromides. The average composition of the butene mixtures formed in these experiments was 17.2 ± 3.3% trans-butene-2, 26.5 ± 1.4% cis-butene-2, and 56.4 ± 2.0% butene-1. In contrast to the mixture of butenes produced by dilute aqueous acid hydrolysis, it has been found that cleavage of the Grignard reagent with phenylacetylene gives almost pure butene-1. 
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\nIn the present investigation, the reaction of the butenyl Grignard reagent has been studied with a wide variety of active hydrogen compounds to see if this type of reaction can be correlated with the earlier formulations of the structure and reaction mechanisms of the butenylmagnesium halide.