DFT Study on the Mechanism of Amides to Aldehydes Using Cp2Zr(H)Cl
DFT Study on the Mechanism of Amides to Aldehydes Using Cp2Zr(H)Cl
复制标题
Cp2Zr(H)Cl对酰胺制醛机理的DFT研究
DOI：
10.1021/om900371u
复制
发表时间：
2010-01
期刊：
影响因子：
2.8
通讯作者：
Zhao, Cunyuan
中科院分区：
文献类型：
--
作者：
Phillips, David Lee;Su, Cheng-Yong;Gao, Hui;Wang, Juping;Xu, Huiying;Zhao, Cunyuan
采用密度泛函理论（DFT）方法，在B3 LYP/6- 31 G（d，p）（Zr为LANL 2DZ）水平上对Cp 2 Zr（H）Cl还原酰胺生成醛的反应机理进行了研究.特别是，进行了详细的研究，涉及一个建议的亚胺阳离子物种的反应机理。我们的计算表明，反应的第一步是通过“内部”作用模式将C − O部分插入Zr−H中，导致形成在先前报道的实验中观察到的Zr−O中间体。在无水条件下，Zr−O中间体的O−C键的断裂导致形成亚胺阳离子，但这个过程在动力学和化学上都是不利的。然而，在含水条件下，Zr−O中间体的O−C键的断裂导致形成高活性的亚胺阳离子中间体，并且该过程在水氢键的协助下发生。
Density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) (LANL2DZ for Zr) level of theory were performed to elucidate the reaction mechanism for the reduction of amides to aldehydes using Cp2Zr(H)Cl as a reducer. In particular, a detailed study was done that involved a proposed iminium cation species in the reaction mechanism. Our calculations suggest the first step of the reaction is the insertion of the C═O moiety into Zr−H through an “inside” mode of action that leads to the formation of a Zr−O intermediate that has been observed in previously reported experiments. Under anhydrous conditions, the cleavage of the O−C bond of the Zr−O intermediate results in the formation of an iminium cation, but this process is both kinetically and thermodynamically unfavorable. Nevertheless, under hydrous conditions, the cleavage of the O−C bond of the Zr−O intermediate leads to the formation of a highly active iminium cation intermediate, and this process occurs with the assistance of water hydrogen bondi...