Regio‐ and Stereoselective Hydrophosphorylation of Ynamides for Synthesizing α ‐Aminovinylphosphine Oxides

This study reported a regio‐ and stereoselectivity hydrophosphorylation of diphenylphosphine oxides and ynamines promoted by trifluoromethanesulfonic anhydride (Tf 2 O) under metal‐free conditions. By regulating the ring‐opening selectivity of in situ generated quaternary phosphonium salts through solvents and ions, various (E)‐α‐aminovinylphosphine oxides were successfully obtained with excellent regio‐ and stereoselectivity. This strategy showed good compatibility with various functional groups under mild conditions. The reaction was further investigated by in situ NMR spectroscopy, and a possible mechanism was also proposed.