A rhodium(III)-catalyzed formal C–H [5 + 1] cyclization of 2-pyrrolyl/indolylanilines with vinylene carbonate has been explored towards the potent assembly of diverse 4-methylpyrrolo[1,2-a]quinoxalines. This established protocol is characterized by an exceedingly simple reaction system, and excellent functional group toleration and yields. Most importantly, entirely distinct from documented [4 + 2] cyclization conversions, herein, the emerging vinylene carbonate firstly presents as a C1 synthon to realize [5 + 1] annulation and shows new chemical reactivity. Biological studies indicate that these prepared products are promising candidates in terms of their antibacterial activity.

A metal-free C–H [5 + 1] annulation reaction of 2-arylanilines with diazo compounds has been achieved, giving rise to two types of prevalent phenanthridines via highly selective C–C cleavage.