Rankin Matthew A, MacLean Darren F, Schatte Gabriele, McDonald Robert, Stradiotto Mark
Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3.
J Am Chem Soc. 2007 Dec 26;129(51):15855-64. doi: 10.1021/ja0768800. Epub 2007 Dec 4.
Treatment of CpRuCl(kappa2-P,N-2b) (2b = 2-NMe2-3-PiPr2-indene) with TlSO3CF3 produced the cyclometalated complex [4]+SO3CF3- in 94% isolated yield. Exposure of [4]+X- (X = B(C6F5)4 or SO3CF3) to Ph2SiH2 (10 equiv) or PhSiH3 afforded the corresponding [Cp(mu-P,N-2b)(H)2Ru=SiRPh]+X- complexes, [5]+X- (R = Ph; X = B(C6F5)4, 82%; X = SO3CF3, 39%) and [6]+X- (R = H; X = B(C6F5)4, 94%; X = SO3CF3, 95%). Notably, these transformations represent the first documented examples of Ru-mediated silylene extrusion via double geminal Si-H bond activation of an organosilane-a key step in the recently proposed Glaser-Tilley (G-T) alkene hydrosilylation mechanism. Treatment of [5]+B(C6F5)4- with KN(SiMe3)2 or [6]+SO3CF3- with NaN(SiMe3)2 afforded the corresponding zwitterionic Cp*(mu-2-NMe2-3-PiPr2-indenide)(H)2Ru=SiRPh complex in 69% (R = Ph, 7) or 86% (R = H, 8) isolated yield. Both [6]+X- and 8 proved unreactive toward 1-hexene and styrene and provided negligible catalytic turnover in the attempted metal-mediated hydrosilylation of these substrates with PhSiH3, thereby providing further empirical evidence for the required intermediacy of base-free Ru=Si species in the G-T mechanism. Isomerization of the P,N-indene ligand backbone in [6]+X-, giving rise to [Cp*(mu-1-PiPr2-2-NMe2-indene)(H)2Ru=SiHPh]+X- ([9]+X-), was observed. In the case of [9]+SO3CF3-, net intramolecular addition of the Ru=Si-H group across the styrene-like C=C unit within the ligand backbone to give 10 (96% isolated yield) was observed. Crystallographic characterization data are provided for [4]+X-, [5]+X-, [6]+X-, 8, and 10.
用三氟甲磺酸铊处理CpRuCl(κ²-P,N-2b)（2b = 2-NMe₂-3-PiPr₂-茚），以94%的分离产率得到环金属化配合物[4]+SO₃CF₃⁻。将[4]+X⁻（X = B(C₆F₅)₄或SO₃CF₃）暴露于二苯基硅烷（10当量）或苯基硅烷中，得到相应的[Cp(μ-P,N-2b)(H)₂Ru=SiRPh]+X⁻配合物，[5]+X⁻（R = Ph；X = B(C₆F₅)₄，82%；X = SO₃CF₃，39%）和[6]+X⁻（R = H；X = B(C₆F₅)₄，94%；X = SO₃CF₃，95%）。值得注意的是，这些转化代表了通过有机硅烷的双偕二硅氢键活化实现Ru介导的硅烯挤出的首个有文献记载的例子——这是最近提出的格拉泽-蒂利（G-T）烯烃硅氢化机理中的关键步骤。用双(三甲基硅基)氨基钾处理[5]+B(C₆F₅)₄⁻或用双(三甲基硅基)氨基钠处理[6]+SO₃CF₃⁻，以69%（R = Ph，7）或86%（R = H，8）的分离产率得到相应的两性离子型Cp*(μ-2-NMe₂-3-PiPr₂-茚基)(H)₂Ru=SiRPh配合物。[6]+X⁻和8对1-己烯和苯乙烯均无反应，并且在尝试用苯基硅烷对这些底物进行金属介导的硅氢化反应时，催化转化率可忽略不计，从而为G-T机理中无碱Ru=Si物种的必要中间体提供了进一步的实验证据。观察到[6]+X⁻中P,N-茚配体主链的异构化，生成了[Cp*(μ-1-PiPr₂-2-NMe₂-茚)(H)₂Ru=SiHPh]+X⁻（[9]+X⁻）。在[9]+SO₃CF₃⁻的情况下，可以观察到Ru=Si-H基团通过分子内净加成到配体主链内类似苯乙烯的C=C单元上，生成10（分离产率96%）。提供了[4]+X⁻、[5]+X⁻、[6]+X⁻、8和10的晶体学表征数据。
