Fig. 1: The reported chiral aldehyde catalytic systems and the asymmetric α−propargylation reaction of amino acid esters (LG = Leaving Group).

a The reported chiral aldehyde-involved catalytic systems. b The reported catalytic asymmetric α−propargylation of amino acid esters. c The chiral aldehyde/nickel catalyzed α−propargylation of N-unprotected amino acid derivatives (this work).