Conjugate addition reactions of some magnesium-based organocuprates with α-ethylenic carbonyl compounds

Abstract

Bromomagnesium diphenylcuprate and the iodomagnesium dimethylcuprate reagent (prepared from 2 RMgX + CuI) react with methyl or ethyl 3-phenylpropenoate and methyl 2-butenoate to give 25–70% yields of the corresponding conjugate addition products. The reactions of these cuprates with 4-methylpent-3-en-2-one, 4-(4-methoxyphenyl)but-3-en-2-one or 1,3-diphenylprop-2-en1-one give the corresponding conjugate adducts in 49–70% yields. In general, the yields are lower when the phenylcopper reagent (prepared from PhMgBr + CuI) is employed.