Direct cyclization of ortho-(1H-pyrrol-1-yl)aryl and heteroaryl carboxylic acids into fused pyrrolizinones

A series of fused heterocyclic compounds based on a pyrrolizinone structure have been prepared from ortho-(1H-pyrrol-1-yl)aryl and heteroaryl carboxylic acids by intramolecular Friedel–Crafts acylation promoted by bis(trichloromethyl) carbonate, in generally good yield without using Lewis acid catalysts.