Regio- and Stereoselective Hydrophosphination Reactions of Alkynes with Phosphine−Boranes:  Access to Stereodefined Vinylphosphine Derivatives

Vinylphosphine−borane complexes are easily synthesized by regio- and stereoselective hydrophosphination of terminal alkynes with use of secondary phosphine−boranes as hydrophosphinating agent. The regioselectivity of the reaction is efficiently controlled by the choice of the activation process: thermal or metal catalyst activation. The vinylphosphine derivatives are purified by chromatography on silica gel. Scalability of the process is demonstrated on a gram scale. This simple route should promote the use of vinylphosphines as building blocks for organic and organometallic chemistry.