Enantioselective Mannich Reaction And The Desymmetrization Reaction Of Meso Aziridines Catalyzed By Phosphonium Salts

Based on the asymmetric reaction catalyzed by phosphoniumsalts which synthesized from-amino acids, two aspects arestudied below:1．Enantioselective Mannich reaction of γ-malonate-substitutedα,β-unsaturated esters with N-Boc imines catalyzed by chiralbifunctional thiourea-phosphonium salts was studied. Usingphosphonium salts as the catalysts, the direct Mannich reactionwas preceded well in toluene at0oC within12-30h to give thecorresponding products with up to99%yield and90%ee.Polysubstituted pyrrolidines were obtained through one steptransformation of the Mannich reaction products.2． Chiral phosphonium salts catalyzed enantioselectivering-opening of meso-aziridines with a series of functionalizedaromatic thiol nucleophiles in CCl4at-10oC within24h to obtainthe products of chiral β-amino thioethers with up to99%yieldand70%ee.