Organocuprates in the Conjugate Addition Reaction
1991; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-08-052349-1.00093-7
Autores Tópico(s)Synthetic Organic Chemistry Methods
ResumoOne of the distinguishing features of the reaction of organocuprates with α,β-unsaturated carbonyl compounds is the overwhelming preference for the 1,4 versus the 1,2 mode of addition.1 Dramatic changes in chemoselectivity are often observed when a copper(I) salt is added to a solution of an organomagnesium or organolithium reagent and an enone. For example, when trans-3-penten-2-one is treated with MeLi, a selective 1,2-addition takes place (99% 1,2). Use of methylmagnesium bromide leads to a mixture of 1,4- and 1,2-addition products (30:70). However, if the same enone is treated with Me2CuLi, prepared from 2MeLi and CuI, only the conjugate addition product is formed (99% 1,4).2
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