Catalytic Asymmetric Synthesis Of Beta,Gamma-Alkynyl Alpha-Amino Esters Via Chemo- And Enantio-Selective Transfer Hydrogenation

An effective chemo- and enantioselective transfer hydrogenation of beta,gamma-alkynyl alpha-imino esters to prepare optically pure beta,gamma-alkynyl alpha-amino esters has been described. The excellent chemoselectivity was achieved by using chiral phosphoric acid catalyzed asymmetric reduction with benzothiazoline as hydride donor. The reaction exhibited good functional group tolerance, providing a range of optically active non-natural amino esters with excellent enantioselectivity.