| 12919015 |
Takaki K, Koshoji G, Komeyama K, Takeda M, Shishido T, Kitani A, Takehira K: Intermolecular hydrophosphination of alkynes and related carbon [bond] carbon multiple bonds catalyzed by organoytterbiums. J Org Chem. 2003 Aug 22;68(17):6554-65.
Intermolecular hydrophosphination of alkynes with diphenylphosphine is catalyzed by a Yb [bond] imine complex, [Yb (eta (2)-Ph (2) CNPh)(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 [bond] 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 [bond] PPh (2) species, followed by protonation. In fact, the Yb [bond] phosphido complex, [Yb (PPh (2))(2)(hmpa)(3)], is obtained from the imine complex and phosphine, which exhibits similar catalyst activity for the hydrophosphination. The empirical rate law is nu = k [catalyst](2) [alkyne](1)[phosphine](0) at least under the standard conditions. |
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