Diphosphination of 1,3-Dienes with Diphosphines under Visible-Light-Promoted Photoredox Catalysis.

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.