Photoinduced Consecutive Ferrous- and Ferric-Catalyzed Single-Electron Transfers

Photoredox catalysis driven by iron has attracted substantial attention due to environmental and economic benefits. Current research predominantly focuses separately on the photoinduced ferric-catalyzed ligand-to-metal charge transfer (LMCT) and photoinduced ferrous-catalyzed electron transfer (ET) pathways, both of which require exogenous oxidants or reductants. Herein, we report a redox-neutral consecutive photoinduced ferric-catalyzed LMCT and ferrous-catalyzed ET for 1,2-dialkylation of alkenes. We find that the ferrous and ferric catalytic species are interconvertible within the reaction system to separately mediate decarboxylation and dehalogenation via the LMCT and ET pathways. The photoinduced iron-catalyzed consecutive LMCT and ET pathways simultaneously generate one alkyl radical and one benzyl radical, enabling regioselective dialkylation of alkenes via radical carbometallation and outer-sphere cross-coupling.