Photoinduced Hydrophosphination of Terminal Alkynes with Tri(o-tolyl)phosphine: Synthesis of Alkenylphosphonium Salts

Abstract

Herein reported is a photoinduced hydrophosphination reaction of terminal alkynes with tri­(o-tolyl)­phosphine to form alkenylphosphonium salts. The reaction is more sustainable than conventional methods since it dispenses with the need for elaborated starting materials and precious transition metals. The o-methyl groups of tri­(o-tolyl)­phosphine play two important roles: (1) to guide the phosphorus radical to add onto the terminal sp carbon and (2) to donate a hydrogen atom onto the developing sp2 carbon radical intramolecularly.

Photocatalytic 1,2-Phosphorus-Migrative [3 + 2] Cycloaddition of Tri(t-butyl)phosphine with Terminal Alkynes

“…In our continuing investigation of the reactivity of phosphonioalkyl radical species, we discovered an unprecedented phosphorus migration reaction. Here, we report a photocatalytic [3 + 2] cycloaddition of tri­( t -butyl)­phosphine with terminal alkynes involving 1,2-phosphorus migration of β-phosphonioalkyl radicals (Figure b).…”