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

Herein, we introduce an electrochemical dehydrogenative [3 + 2]/[5 + 2] annulation of easily available N -arylacrylamides 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.