Electrochemical Dehydrogenative [3 + 2]/[5 + 2] Annulation of N-Arylacrylamides with γ,σ-Unsaturated Malonates via Direct C(sp³)–H/C(sp²)–H Functionalization

Abstract

Herein, we introduce an electrochemical dehydrogenative [3 + 2]/[5 + 2] annulation of easily available Narylacrylamides with γ,σ-unsaturated malonates through C(sp 3 )−H/C(sp 2 )−H functionalization. The employment of inexpensive ferrocene as the redox catalyst allows access to diverse benzo[b]azepin-2-ones in moderate to excellent yields without stoichiometric oxidants. This protocol features broad substrate scope and excellent selectivity, and mechanistic studies indicated that the reaction proceeded through the oxidation of a C(sp 3 )−H bond to generate an alkyl radical, radical addition across the C�C bond, [3 + 2]/ [5 + 2] annulations, and C(sp 2 )−H functionalization cascades.