Visible-Light-Driven Selective Alkenyl C-P Bond Cleavage of Allenylphosphine Oxides

An efficient method for highly selective alkenyl C-P bond cleavage, enabled by organic dyes and visible-light irradiation, was developed. This novel protocol involves a highly regioselective radical pathway initiated by singlet oxygen, affording diverse alkynyl phosphinates with good-to-excellent yields. Mechanistic studies and density functional theory calculations suggested an intramolecular process involving phosphorus migration, instead of phosphorus radical formation, at the early stage of the reaction.