Visible‐Light Induced C(sp2)−H Amidation with an Aryl–Alkyl σ‐Bond Relocation via Redox‐Neutral Radical–Polar Crossover

Abstract

AbstractWe report an approach for the intramolecular C(sp2)−H amidation of N‐acyloxyamides under photoredox conditions to produce δ‐benzolactams with an aryl‐alkyl σ‐bond relocation. Computational studies on the designed reductive single electron transfer strategy led us to identify N‐[3,5‐bis(trifluoromethyl)benzoyl] group as the most effective amidyl radical precursor. Upon the formation of an azaspirocyclic radical intermediate by the selective ipso‐addition with outcompeting an ortho‐attack, radical–polar crossover was then rationalized to lead to the rearomative ring‐expansion with preferential C−C bond migration.