A computational study of phosphine ligand effects in Suzuki-Miyaura coupling
A computational study of phosphine ligand effects in Suzuki-Miyaura coupling
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DOI：
10.1016/j.molcata.2010.02.021
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发表时间：
2010-06-01
影响因子：
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通讯作者：
Harvey, Jeremy N.
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文献类型：
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作者：
Jover, Jesus;Fey, Natalie;Harvey, Jeremy N.
用密度泛函理论方法研究了Pd(PMe3)(2)、Pd(P(CF3)(3))(2)、Pd(PPh3)(2)和Pd((PBu3)-Bu-t)(2)四种不同的单膦钯催化剂Pd(PMe3)(2)、Pd(PPh3)(2)和Pd((PBu3)-Bu-t)(2)催化PhBr与PhB(OH)(-)偶联反应的全催化循环。研究了反应的各个步骤，分析了配体之间的差异，特别关注了配体的解离和催化剂的再生过程，以及典型的氧化加成、过渡金属和还原消除等交叉耦合步骤。对计算得到的能垒进行了多元线性回归，以量化不同膦对反应关键步骤的配位体效应。这些与催化活性有关的配体效应是用膦给体/受体和空间构型描述的。回归模型表明，氧化加成主要受电子效应控制，而过渡金属作用和还原消除过程受两种配体效应的共同控制。对于跨金属作用，吸电子的配体降低了能垒。(C)2010爱思唯尔B.V.保留所有权利。
DFT calculations have been used to explore the full catalytic cycle of the Suzuki-Miyaura coupling between PhBr and PhB(OH)(3)(-) with four different palladium monophosphine catalysts derived from Pd(PMe3)(2), Pd(P(CF3)(3))(2), Pd(PPh3)(2) and Pd((PBu3)-Bu-t)(2). All the steps of the reaction have been studied and the differences between the ligands have been analyzed; special attention has been devoted to the ligand dissociation and catalyst regeneration processes, as well as the typical cross-coupling steps of oxidative addition, transmetallation and reductive elimination. Multiple linear regressions of the computationally derived energy barriers have been carried out in order to quantify the ligand effects of the different phosphines on the key steps of the reaction. These ligand effects, relevant to the catalytic activity, are described in terms of the phosphine donor/acceptor and steric features. The regression models show that oxidative addition is mainly governed by electronic effects whereas the transmetallation and the reductive elimination processes are controlled by a mixture of both ligand effects. For transmetallation, electron-withdrawing ligands lower the energy barrier. (C) 2010 Elsevier B.V. All rights reserved.