The reaction of [RuCl(η5-C9H7)(PPh3)2] with an excess of 1-ethynyl-1-cyclohexanol and NaPF6 in refluxing methanol yielded the allenylidene complex [RuCCC(C13H20)}(η5-C9H7)(PPh3)2][PF6] 1 via an unprecedented coupling of two molecules of the propargyl (prop-2-ynyl) alcohol derivative. Complex 1 can also be obtained by reaction of the vinylvinylidene derivative [RuCC(H)R}(η5-C9H7)(PPh3)2][PF6] 2 (R = 1-cyclohexenyl) with 1-ethynyl-1-cyclohexanol or 1-ethynylcyclohexene in refluxing methanol. The behaviour of 2 towards other 1-alkyn-3-ols has been studied but only the replacement of the vinylidene moiety by the propargyl alcohols, via an η1-vinylideneâη2-alkyne tautomerization process, to generate both vinylvinylidene [RuCC(H)R}(η5-C9H7)(PPh3)2][PF6] (R = 1-cyclopentenyl, 1-cycloheptenyl or 1-cyclooctenyl) or allenylidene [Ru(CCCR2)(η5-C9H7)(PPh3)2][PF6] (R = Ph or R2 = 2,2â²-biphenyldiyl) complexes along with 1-ethynylcyclohexene was observed. A similar 1,3-enyne elimination also takes place in the reaction of 2 with phenylacetylene or acetonitrile to afford [RuCC(H)Ph}(η5-C9H7)(PPh3)2][PF6] and [Ru(NCMe)(η5-C9H7)(PPh3)2][PF6], respectively. On the basis of these observations a mechanism for the formation of 1 is proposed. The allenylidene complex 1 regioselectively reacts with NaR, in THF at â20 °C, to yield the neutral Ï-alkynyl derivatives [RuCCC(C13H20)R}(η5-C9H7)(PPh3)2] (R = CN or OMe). Protonation of the R = CN derivative with HBF4·Et2O, in diethyl ether at â20 °C, afforded the cationic vinylidene complex [RuCC(H)C(C13H20)CN}(η5-C9H7)(PPh3)2][BF4]. In contrast, protonation with R = OMe gives back the starting allenylidene derivative 1.
[RuCl(η^5-
C9H7)(PPh3)2] 与过量的 1-
乙炔基-1-
环己醇和 NaPF6 在热回流的
甲醇中反应,生成了不同寻常的联烯基复合物 [RuCCC(
C13H20)}(η^5- )(PPh3)2][PF6] 1,这个反应是由两个
丙炔(丙-2-炔基)醇衍
生物的分子偶联而成的。复合物 1 也可以通过在热回流的
甲醇中,将
乙烯-
乙烯基衍
生物 [RuCC(H)R}(η^5- )(PPh3)2][PF6] 2(R = 1-
环己烯基)与 1-
乙炔基-1-
环己醇或 1-
乙炔基
环己烯反应获得。已经研究了 2 对其他 1-炔-3-醇的行为,但仅观察到通过 η^
1-乙烯基-η^2-炔的互变异构化过程,将
乙烯基部分替换为
丙炔醇,产生
乙烯-
乙烯基 [RuCC(H)R}(η^5- )(PPh3)2][PF6](R = 1-
环戊烯基、1-
环庚烯基或 1-环
辛烯基)或联烯基 [Ru(CCCR2)(η^5- )(PPh3)2][PF6](R = Ph 或 R2 = 2,2′-
联苯基)复合物以及 1-
乙炔基
环己烯。类似的 1,3-炔烯消除反应也发生在 2 与苯基炔或
乙腈的反应中,分别生成 [RuCC(H)Ph}(η^5- )(PPh3)2][PF6] 和 [Ru(NCMe)(η^5- )(PPh3)2][PF6]。基于这些观察,提出了 1 的形成机制。联烯基复合物 1 在 -20 °C 的 THF 中与 NaR 进行区域选择性反应,生成中性的 σ-炔基衍
生物 [RuCCC( )R}(η^5- )(PPh3)2](R = CN 或 OMe)。将 R = CN 的衍
生物用
HBF4·Et2O 在 -20 °C 的二
乙醚中质子化,生成了阳离子
乙烯基复合物 [RuCC(H)C( )CN}(η^5- )(PPh3)2][BF4]。相反,使用 R = OMe 进行质子化则恢复了起始的联烯基衍
生物 1。