First-Principles Molecular Dynamics Analysis of Ligand-Free Suzuki–Miyaura Cross-Coupling in Water: Transmetalation and Reductive Elimination,The Journal of Physical Chemistry C

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First-Principles Molecular Dynamics Analysis of Ligand-Free Suzuki–Miyaura Cross-Coupling in Water: Transmetalation and Reductive Elimination
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2017-09-05 00:00:00 , DOI: 10.1021/acs.jpcc.7b06972
Teruo Hirakawa ₁ , Yuta Uramoto ₁ , Susumu Yanagisawa ₂ , Takashi Ikeda ₃ , Kouji Inagaki _{1,

4} , Yoshitada Morikawa _{1,

4,

5}

Affiliation

We investigated the transmetalation step of the Suzuki–Miyaura cross coupling reaction (SMR) catalyzed by ligand-free Pd atom or Pd-X^– (X = Cl or Br) using first-principles molecular dynamics simulations with an explicit solvent model. When starting from the single Pd atom, the halogen anion bound to the Pd was not replaced by organoboronate species and instead remained bound to the Pd throughout the transmetalation step. However, when starting from the Pd-X^– catalyst, one of the two halogen anions was released from the first coordination sphere of the Pd during transmetalation. Therefore, the products after the transmetalation starting with either the single Pd atom or the Pd-X^– were the same. We concluded that Pd-X^– is the active species of the ligand-free Pd catalyst for the SMR. The overall activation free energies for transmetalation and reductive elimination were relatively low, estimated to be at most, 8.1 kcal/mol for X = Br and 8.4 kcal/mol for X = Cl, respectively, leading to the efficient turnover of the SMR. We ascribe the origin for the suppression of the catalytic reactivity of the ligand-free SMR for PhCl to the larger activation barrier in the oxidative addition step, which causes the aggregation of Pd catalysts.

中文翻译：

水中无配体的铃木-宫浦交叉偶联的第一性原理分子动力学分析：过渡金属化和还原消除

我们研究了通过配体-自由钯原子或催化的Suzuki-Miyaura交叉偶联反应（SMR）的转移金属化步骤的Pd-X ^-（X = Cl或Br），使用第一原理分子动力学模拟使用显式溶剂模型。当从单个Pd原子开始时，键合到Pd上的卤素阴离子不会被有机硼酸酯类所取代，而是在整个过渡金属化步骤中保持键合到Pd上。然而，从PD-X开始时^-催化剂，两个卤素阴离子之一是从Pd所构成的第一配位层转移金属化过程中释放。因此，从任一单钯原子或钯-X的转移金属化之后的产物^-是相同的。我们得出结论，Pd-X ^–是SMR的无配体Pd催化剂的活性物种。用于金属转移和还原消除的总活化自由能较低，估计最高分别为X = Br为8.1 kcal / mol和X = Cl为8.4 kcal / mol，从而导致SMR的有效转换。我们归因于在氧化加成步骤中抑制无配体的SMR对PhCl的催化反应性对较大的活化势垒的起因，这会导致Pd催化剂的聚集。

更新日期：2017-09-05

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