Carbene-Catalyzed Asymmetric Synthesis of Thiophene-Fused Lactams

A mild and environmentally friendly construction of thieno-fused lactam scaffolds has been successfully developed through NHC-catalyzed [3 + 3] annulation of bromoenals and thiophen-3-amines. A diverse range of thieno[3,2-<i>b</i>]pyridinones were efficiently synthesized in moderate-to-excellent yields with good-to-excellent enantioselectivities. Notably, protecting-group-free thiophen-3-amines were compatible with this strategy in the presence of the green solvent 2-MeTHF.