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

Abstract

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