157261-57-9Relevant academic research and scientific papers
A new reactive system for catalytic bis-silylation of acetylenes and olefins
Ozawa, Fumiyuki,Sugawara, Mitsuru,Hayashi, Tamio
, p. 3237 - 3243 (2008/10/08)
Reaction of diphenylacetylene (1a) with Me3SiSiF2Ph (1 equiv) in toluene in the presence of a palladium catalyst (1 mol %) generated in situ by mixing [Pd(η3-allyl)Cl]2 and PMe2Ph (2.2 equiv/Pd) was completed in 1.4 h at room temperature to give the bis-silylation product (Z)-1-(difluorophenylsilyl)-1,2-diphenyl-2-(trimethylsilyl)ethene (2a) in 95% yield. In similar catalytic systems, a variety of acetylenes and olefins, including 3-hexyne, 1-phenyl-1-propyne, phenylacetylene, 1-octyne, norbornene, styrene, and 1-octene, were bis-silylated in 64-96% yields. The highly reactive nature of the present catalytic system was studied in stoichiometric systems. The presumed intermediates trans-Pd(SiMe3)(SiF2Ph)L2 (L = PMe3 (4a), PMe2Ph (4b)) were prepared by oxidative addition of Me3SiSiF2Ph toward Pd(styrene)L2 complexes (L = PMe3 (3a), PMe2Ph (3b)). Complex 4b reacted with diphenylacetylene (3 equiv) in toluene-d8 at -20°C to give the bis-silylation product (Z)-2a in 82% yield together with Pd(PhC≡CPh)(PMe2Ph)2 (93%). Treatment of 4a with dimethyl acetylenedicarboxylate (1 equiv) in toluene at -20°C instantly formed a palladium(0) complex coordinated with bis-silylated olefin, Pd{(Z)-(MeO2C)(Me3Si)C=C(SiF2Ph)(CO 2Me)}(PMe3)2 (6). The structure of 6 was determined by an X-ray diffraction study. Crystal data for 6·THF: C21H38O4P2F2-Si 2Pd·C4H8O, a = 15.585(2) A?, b = 12.438(2) A?, c = 17.652(2), β = 93.86(1)°, V = 3413.9(8) A?3, monoclinic, P21/n, Z = 4.
