Stereoselective Intermolecular Thiophosphinations of Terminal Alkynes

Significance

The authors report a highly stereoselective intermolecular radical thiophosphination of terminal alkynes using the V-40 radical initiator. Due to the sensitivity of the products to oxidation forming phosphine oxides, the products were sulfidated in situ using elemental sulfur. A variety of alkyl- and aryl-substituted terminal alkynes can be used for this two-step reaction in good yields and E/Z selectivities. Desulfidation to the corresponding phosphines can be accomplished by radical means.