Enantioselective N‐Heterocyclic Carbene Catalysis that Exploits Imine Umpolung

Abstract The catalytic umpolung of imines remains an underdeveloped approach to reaction discovery. Herein we report an enantioselective aza‐Stetter reaction that proceeds via imine umpolung using N‐heterocyclic carbene catalysis. The reaction proceeds with high levels of enantioselectivity (all ≥96:4 er) and good generality (21 examples). Mechanistic studies are reported and are consistent with turnover‐limiting addition of the NHC to the imine.