Diastereoselective alkynylation of chiral phosphinoylimines: preparation of optically active propargylamines

Chiral phosphinoylimines were prepared from methylphenylphosphonamides and tested as new chiral and activated imines. The addition of aluminum acetylides was proved to be highly diastereoselective while lithium or magnesium acetylides gave poor results. The cleavage of the chiral auxiliary was done under mild conditions and allows the recovery of the starting phosphonamide without loss of optical purity.