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钌催化剂RuH_2(CO)(PPh_3)_3使Murai反应中芳香酮β位C–H键的催化活化反应具有极高的产率与选择性.本文采用密度泛函(DFT)方法研究了钌配合物催化芳香酮邻位C–H键活化的反应机理,剖析了芳香酮C–H键活化反应中产生区域选择性的原因.计算结果表明,C–H键的活化位垒为1.1 kcal/mol,从反应动态学角度很好地解释了该反应的区域选择性.通过路径a与路径b的比较,发现C=C双键更容易插入到Ru–H键而不是Ru–C键中.另外,无论C–C键形成(C–C活化过程)出现在路径a的烯烃插入基元反应,还是出现在路径b的还原消除基元反应,C–C键形成步骤都是整个催化反应的决速步骤.与路径a和b比较,反应路径c中C–C键形成过程的空间位阻较大,能垒也更高.
The ruthenium catalyst RuH_2 (CO) (PPh_3) _3 has a very high yield and selectivity for the catalytic activation of the C-H bond of the aromatic ketones in the Murai reaction.In this paper, the density functional theory (DFT) Catalyzed the reaction mechanism of the C-H bond at the ortho position of the aromatic ketones, and analyzed the reasons for the regioselectivity in the C-H activation reaction of the aromatic ketones. The calculated results show that the activation barrier of C-H bonds is 1.1 kcal / mol, The regioselectivity of this reaction is well explained from the viewpoint of reaction kinetics. Comparing path a with path b, we found that C = C double bond is more easily inserted into Ru-H than Ru-C. In addition, Regardless of whether the C-C bond formation (C-C activation process) occurs at the olefin insertion elementary reaction at path a or the reduction elimination elementary reaction at path b, the C-C bond formation step is the rate of the overall catalytic reaction As compared with path a and b, the steric hindrance of C-C bond formation in reaction path c is larger and the energy barrier is higher.