Photoinduced Homolysis of the Ni-P Bond via Ligand to Metal Charge Transfer for C-P Bond Formation in Nickel Catalysis.

Photoinduced homolysis of Ni II -carbon and -heteroatom bonds has been well studied for carbon-heteroatom couplings, but homolysis of the Ni II -P bond is still undisclosed. Herein, we describe the homolysis of Ni II -P bonds via ligand to metal charge transfer to access active nickel(I) complexes and phosphorus-centered radicals under visible-light irradiation for C-P couplings of diaryl phosphine oxides with aryl bromides. Experimental studies demonstrated that visible light enabled homolysis of the Ni II -P bond and the Ni I /Ni III self-sustained cycle was involved in C-P bond formation. Furthermore, homolysis of the Ni II -P bond can be applied to the hydrophosphination of [1.1.1]propellane in single-nickel photocatalysis.