A facile synthesis of tetrahydroimidazo[1,2-a]pyridines and tetrahydrobenzo[b]imidazo[1,2,3-ij][1,8]naphthyridines through NHC-catalyzed cascade annulations

A new efficient approach for the synthesis of tetrahydroimidazo[1,2-a]pyridines and tetrahydrobenzo [b]imidazo[1,2,3-ij][1,8]naphthyridines with biological significance was successfully developed through a NHC-catalyzed cascade C-C bond and C-N bond formation process. This new alternative approach for the assembly of these multi-functionalized nitrogen bridgehead-fused heterocycles features mild conditions, moderate to high yields and operational simplicity.