|Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
1. Hydrosilylation of Olefins and Dehydrogenative Double Silylation of Conjugated Dienes Catalyzed by Lanthanide Amide Complexes.
Lanthanide-imine complex, [Yb(η^2-ph_2CNPh)(hmpa)_3] (1), and diamide complexes, prepared from 1 and equimolar amounts of Ph_2NH, catalyzed hydrosilylation of olefins with PhSiH_3 and Ph_2SiH_2 very effectively. On the other hand, the catalysts induced dehydrogenative double silylation of conjugated dienes to give selectively 1,4-bis(silyl)-2-butenes instead of expected 1,4- and 1,2-hydrosilylation products. It has been found that hydride and silyl species, [Yb[-H and [Yb]-Si, are generated together from the catalysts and hydrosilanes and that the former reacts with the olefins and the latter with the dienes predominantly.
2. Hydrophosphination of Alkynes and Related Carbon-Carbon Multiple Bonds Catalyzed by Lanthanide-Imine Complexes.
Intermolecular hydrophosphination of alkynes with diphenylphosphine is catalyzed by a Yb-imine complex 1 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. Region- 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-PPh_2 species, followed by protonation. In fact, the Yb-phosphide 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 v=k [catalyst]^2[alkynes]^1[phosphine]^0 at least under the standard conditions.