Cβ(sp2)−H Bond Activation of α,β-Unsaturated Ketones Promoted by a Hydride-Elongated Dihydrogen Complex: Formation of Osmafuran Derivatives with Carbene, Car

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• 作者：Marí ; a L. Buil ; Miguel A. Esteruelas ; Karin Garcé ; s ; Montserrat Olivá ; n ; Enrique Oñ ; ate
• 刊名：Organometallics
• 出版年：2008
• 出版时间：September 22, 2008
• 年：2008
• 卷：27
• 期：18
• 页码：4680-4690
• 全文大小：340K
• 年卷期：v.27,no.18(September 22, 2008)
• ISSN：1520-6041

文摘

Complex [OsH(η²-H₂)(η²-CH₂CH-o-C₅H₄N)(PⁱPr₃)₂]BF₄ (1) reacts with methyl vinyl ketone in the absence of solvent to give [OsH{CHCHC(O)CH₃}₂(PⁱPr₃)₂]BF₄ (2), which can be described as two osmafurans joined by a common [OsH(PⁱPr₃)₂]⁺ fragment. The hydride ligand of 2 is fairly acidic. Thus, its treatment with sodium methoxide produces the deprotonation of the metal center to give Os{CHCHC(O)CH₃}₂(PⁱPr₃)₂ (3). The reaction is not reversible; the protonation of 3 with HBF₄·OEt₂ leads to [e5" construct="bar">Os{CHCHC(e5">O)CH₃}{CHCH₂C(O)CH₃}(PⁱPr₃)₂]BF₄ (4), which in dichloromethane is unstable and evolves into [Os{CHCHC(O)CH₃}Cl{CCHC(CH₃)OH}(PⁱPr₃)₂]BF₄ (5), containing an enolcarbyne ligand. In the solid state the anion of 5 is associated with the OH-hydrogen of the enol, by means of an H···F hydrogen bond. In dichloromethane the H···F hydrogen bond is broken and DFT calculations suggest that the OH-hydrogen atom forms an H···Cl hydrogen bond with the chlorine ligand. In the absence of solvent, complex 1 reacts with benzylideneacetophenone and benzylideneacetone to give [Os{C(Ph)CHC(O)R}(η²-H₂){κ-C-[HNC₅H₃Et]}(PⁱPr₃)₂]BF₄ (R = Ph (6), CH₃ (10)), containing a NH-tautomerized 2-ethylpyridine ligand. Complexes [Os{C(Ph)CHC(O)R}(η²-H₂){(CH₃CN)}(PⁱPr₃)₂]BF₄ (R = Ph (8), CH₃ (11)) and [e9" construct="bar">Os{C₆H₄C(e9">O)CHCHPh}(η²-H₂){(CH₃CN)}(PⁱPr₃)₂]BF₄ (9) have been also isolated and characterized. The X-ray structures of 2, 5, and 6 are reported.