Synthesis of Stable N-H Imines with a Benzo[7,8]indolizine Core and Benzo[7,8]indolizino[1,2- c ]quinolines via Copper-Catalyzed Annulation of α,β-Unsaturated O -Acyl Ketoximes with Isoquinolinium N -Ylides.

A copper-catalyzed annulation of α,β -unsaturated O -acyl ketoximes with isoquinolinium N -ylides has been developed for the concise synthesis of stable N-H imines with a benzo[7,8]indolizine core. When β-(2-bromoaryl)- α,β -unsaturated O -acyl ketoximes are used as the starting materials, a cascade cyclization occurs to afford the benzo[7,8]indolizino[1,2- c ]quinolines.