Copper (II)/RuPHOX-Catalyzed Enantioselective Mannich-Type Reaction of Glycine Schiff Bases with Cyclic Ketimines

摘要

A Cu(II)/RuPHOX-catalyzed enantioselective Mannich-type reaction of glycine Schiff bases with cyclic ketimines was developed, affording chiral alpha,ss-diamino acid derivatives in good yields with moderate to good ee and dr values. This provides an efficient methodology for furnishing chiral C-beta-tetrasubstituted alpha,beta-diamino acid precursors. The catalytic system is compatible with a series of substrates. In addition, an interesting nonlinear effect of the catalyst's enantiomeric composition on reaction enantioselectivity was observed.