Catalytic, Enantioselective alpha-Alkylation of Azlactones with Nonconjugated Alkenes by Directed Nucleopalladation

摘要

A palladium(II)-catalyzed enantioselective alpha-alkylation of azlactones with nonconjugated alkenes is described. The reaction employs a chiral BINOL-derived phosphoric acid as the source of stereoinduction, and a cleavable bidentate directing group appended to the alkene to control the regioselectivity and stabilize the nucleopalladated alkylpalladium(II) intermediate in the catalytic cycle. A wide range of azlactones were found to be compatible under the optimal reaction conditions to afford products bearing alpha,alpha-disubstituied alpha-amino-acid derivatives with high yields and high enantioselectivity.