Dual Ligands Unlocking Iron and Halogen-Containing Carboxylates-based Photocatalysis for Chloro/Fluoro-Polyhaloalkylation of Alkenes

Herein, we demonstrate a practical dual ligand-enabled iron photocatalysis paradigm—translating all kinds of halogen-containing carboxylates (CnXmCOO−, X: F, Cl, Br) into CnXm radicals for the valuable chloro/fluoro-polyhaloalkylation of non-activated alkenes with easily available trichloroacetonitrile/Selectfluor as the electrophilic halogenation reagent. The modularly in-situ assembly of the effective iron and CnXmCOO−-based light-harvesting species using the two ligands—OMe/CF3-substituted bipyridine and acetonitrile/trichloroacetonitrile is evidenced by detailed mechanistic studies. The late-stage modification, low loading amount of iron (TON: 257) and feasible gram-scale synthesis show the utility of this protocol. We thus anticipate that the dual ligand-enabled iron photocatalysis paradigm may have an aptitude for activation and transformation of inert bulk chemicals.