Acyl radical cyclisation onto pyrroles

Synthetically useful [1,2-a]-fused pyrroles, e.g. 2,3-dihydro-1H-pyrrolizidines substituted in the 1- and 7-positions, have been generated by acyl radical cyclisation onto pyrroles using N-(ω-acyl)-radicals generated from acyl-selenide precursors. The protocol does not require high pressures of CO. Mechanistic studies indicate the key role of azo radical initiators as oxidants of the intermediate π-radicals.