Catalytic Asymmetric Michael Reaction under Phase-Transfer Catalysis: Construction of Chiral Tetrasubstituted Carbon and Its Application to the Synthesis of a Chiral Pyrrolidone

A catalytic asymmetric Michael reaction using Schiff bases promoted by D 2 -symmetrical ammonium salts as phase-transfer catalysts is described.The reaction of glycine Schiff base (1a) gave the Michael adduct with up to 91% ee and tetrasubstituted carbons was also constructed using alanine Schiff base (3a) with up to 63% ee.