An Ir(ppy)-catalyzed vic-diphosphination of styrenes with MeSi-PPh and NFSI proceeds under blue LED irradiation to afford the corresponding bis(diphenylphosphino)ethane derivatives without any formation of hydrophosphination byproducts, which are inevitable and problematic under the previous Cu/NHC catalysis. Additionally, the visible-light-promoted photoredox catalysis enables the diphosphination of relatively challenging aliphatic alkenes and β-substituted styrene.

A ring-opening diphosphination of methylene-and vinylcyclopropanes with tetraaryldiphosphines (Ar 2 P−PAr 2 ) has been developed to afford the corresponding 1,3-diphenylphosphinopropane-and 1,3-diphenylphosphinopentane-type bidentate ligands, respectively. The reaction proceeds under bromine cation-initiated, visible-light-promoted photoredox catalysis at ambient temperature. Owing to the ready availability of functionalized diphosphines, the electronically diverse MeO-and CF 3 -substituted bidentate ligands are also easily prepared.

A diphosphination of 1,3-dienes with tetraaryl­diphosphines proceeds under Ir­(ppy)3-promoted photoredox catalysis to form the corresponding 1,4-diphosphino-2-butenes in good yields with good regioselectivity. The key to success is the addition of a Br+ additive. Subsequent double bond hydrogenation successfully delivers the 1,4-bis­(diphenyl­phosphino)­butane (DPPB) derivatives with uniquely large bite angles. Thus, the present method can provide a facile access to DPPB-type ligands, which are of great importance in transition metal catalysis, from readily available diene substrates.

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An N-bromosuccinimide (NBS)-initiated vic-diphosphination of styrenes with diphosphines proceeds under visible-light-promoted Ir(ppy)3 photoredox catalysis to deliver the corresponding 1,2-diphosphinoethane derivatives in good yields. The NBS is a bromine cation source and generates a bromophosphine, which undergoes a single-electron reduction by the excited iridium species to form phosphinyl radicals of key species in the diphoshination reaction. The newly developed photoredox catalysis demonstrates better reaction efficiency, functional group compatibility, and scalability than the previous photocatalysis using N-fluorobenzenesulfonimide (NFSI) and silylphosphine.