Intermolecular hydrophosphination of alkynes and related carbon-carbon multiple bonds catalyzed by organoytterbiums

Intermolecular hydrophosphination of alkynes with diphenylphosphine is catalyzed by a Yb-imine complex, [Yb(eta(2)-Ph2CNPh)(hmpa)(3)], to give alkenylphosphines and phosphine oxides after oxidative workup in good yields under mild conditions. This reaction is also applicable to various carbon-carbon multiple bonds such as conjugated diynes and dienes, allenes, and styrene derivatives. Regio- and stereoselectivity and the scope and limitation of the present reaction clearly differ from those of the corresponding radical reaction. Instead, the reaction takes place through insertion of alkynes to a Yb-PPh2 species, followed by protonation. In fact, the Yb-phosphido complex, [Yb(PPh2)(2-)(hmpa)(3)], is obtained from the imine complex and phosphine, which exhibits similar catalyst activity for the hydrophosphination. The empirical rate law is v = k [catalyst](2) [alkyne](1) [phosphine](0) at least under the standard conditions.