N-Heterocyclic carbene-catalyzed remote C(sp3)–H acylation of amides

An N-heterocyclic carbene catalyzed benzylic C–H acylation of o-alkyl benzamides and cascade cyclization is developed through a radical-mediated 1,5-hydrogen atom transfer (HAT) mechanism. Different from photoredox catalysis, this light-free approach enables the generation of amidyl radicals through single-electron transfer (SET) with Breslow enolates. The mild process tolerates most common functional groups and delivers a variety of dihydroisoquinolinones in moderate to high yields. The electrochemical character of the aryloxyamide is consistent with the hypothesis of ground-state SET and a plausible mechanism for the organocatalytic transformation is proposed.