Computational Study on the Catalytic Role of Pincer Ruthenium(II)-PNN Complex in Directly Synthesizing Amide from Alcohol and Amine: The Origin of Selectivity of Amide over Ester and Imine
Computational Study on the Catalytic Role of Pincer Ruthenium(II)-PNN Complex in Directly Synthesizing Amide from Alcohol and Amine: The Origin of Selectivity of Amide over Ester and Imine
复制标题
钳钌(II)-PNN配合物在醇和胺直接合成酰胺中的催化作用的计算研究：酰胺相对于酯和亚胺选择性的起源
DOI：
10.1021/om200620n
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发表时间：
2011-10-10
期刊：
影响因子：
2.8
通讯作者：
Wang, Zhi-Xiang
中科院分区：
文献类型：
--
作者：
Li, Haixia;Wang, Xiaotai;Wang, Zhi-Xiang
用密度泛函理论研究了钳形配合物Ru（II）-PNN（PNN = 2-（二叔丁基膦甲基）-6-二乙基氨基甲基）吡啶催化胺与伯醇反应生成酰胺的机理.结果导致我们提出了一个催化循环，包括四个阶段：（第一阶段）醇脱氢醛，（第二阶段）耦合醛与胺形成半缩醛胺，（第三阶段）半缩醛胺脱氢酰胺，和（第四阶段）催化剂再生通过H2消除的反式钌二氢化物络合物在两个脱氢阶段。这两个脱氢反应都是通过双功能双氢转移机理而不是β-H消除机理进行的。酰胺相对于酯的选择性取决于偶联阶段，其中醛-胺偶联得到半缩醛胺比醛-醇偶联得到半缩醛更有利。竞争对手之间的竞争…
Density functional theory calculations have been performed to investigate the mechanism of the reactions of amines with primary alcohols to produce amides, catalyzed by the pincer complex Ru(II)-PNN (PNN = 2-(di-tert-butylphosphinomethyl)-6-diethylaminomethyl)pyridine). The results lead us to propose a catalytic cycle that includes four stages: (stage I) alcohol dehydrogenation to aldehyde, (stage II) coupling of aldehyde with amine to form hemiaminal, (stage III) hemiaminal dehydrogenation to amide, and (stage IV) catalyst regeneration via H2 elimination of the trans Ru dihydride complex produced in the two dehydrogenation stages. Both of the dehydrogenation reactions proceed via the bifunctional double hydrogen transfer mechanism rather than the β-H elimination mechanism. The selectivity of amide over ester is determined by the coupling stage in which the aldehyde∧amine coupling to give hemiaminal is more favorable than aldehyde∧alcohol coupling to give hemiacetal. The competition between dehydrogenatio...