N-Heterocyclic Carbene-Catalyzed Enantioselective Annulation of 2-Amino-1h-indoles and Bromoenals for the Synthesis of Chiral 2-Aryl-2,3-dihydropyrimido[1,2-a]indol-4 (1H)-Ones.

An efficient N-heterocyclic carbene (NHC)-catalyzed enantioselective [3 + 3] annulation of 2-bromoenals with 2-amino-1H-indoles has been developed. A series of functionalized 2-aryl-2,3-dihydropyrimido[1,2-a]indol-4(1H)-ones were synthesized using NHCs as the catalyst in good yields with high to excellent enantioselectivities.