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

Abstract

© 2021 Wiley-VCH GmbH.We 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.