Alkylation of Allylic Derivatives. 8. Regio- and Stereochemistry of Alkylation of Allylic Carboxylates with Lithium Methylcyanocuprate

Article abstract of DOI:10.1021/jo00177a006

Alkylation of 5-methyl-2-cyclohexenyl acetate (1-OAc) with lithium methylcyanocuprate (LiCu(CN)Me) is regiospecific (>90 percent excess γ-alkylation) and sterospecific (>95 percent anti alkylation).In the bicyclo<3.2.1>oct-3-en-2-yl system (3), alkylation is stereoselective (both isomers give exo alkylation) and regiospecific (excess γ-alkylation).Alkylation of trans-α-methyl-γ-mesitylallyl acetate (8-OAc) with LiCu(CN)Me gives 57 percent α- and 43 percent γ-alkylation as compared to >97 percent α-alkylation with LiCuMe2.Mechanistic implications are discussed.