Enantioselective Syntheses of α-Silyl Amines via a Copper-N-Heterocyclic Carbene Catalyzed Nucleophilic Silicon Transfer to Imines

We developed an efficient and enantioselective method for the synthesis of chiral alpha-silyl amines. In the presence of a copper(I)-chiral monodentate N-heterocyclic carbene complex (5 mol%), smooth nucleophilic silicon transfer from Me(2)PhSiBpin (pin = pinacolato) to tosyl-protected aldimines affords the corresponding alpha-silyl amines in 77-93% yields over 15 examples and satisfactory ee of 79-99%. The asymmetric silylation of ketimines was also explored.