Photocatalytic Cycloaddition Reaction of Triarylphosphines with Alkynes Forming Cyclic Phosphonium Salts

Herein reported is a photocatalytic cycloaddition reaction of triarylphosphines with alkynes. Phosphonium salts of unique bicyclic structures are synthesized through a radical pathway under mild reaction conditions. The phosphonium salts are subjected to the Wittig olefination reaction to afford structurally interesting phosphine oxides.