Oxidative carbonylation of phenylacetylene catalyzed by Pd(II) and Cu(I): Experimental tests of forty-one computer-generated mechanistic hypotheses
Oxidative carbonylation of phenylacetylene catalyzed by Pd(II) and Cu(I): Experimental tests of forty-one computer-generated mechanistic hypotheses
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DOI：
10.1016/s1381-1169(97)00193-3
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发表时间：
1998-03-12
影响因子：
--
通讯作者：
Temkin, ON
中科院分区：
文献类型：
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作者：
Bruk, LG;Gorodskii, SN;Temkin, ON
本文以Pd（Ⅱ）和Cu（Ⅰ）催化苯乙炔氧化羰基化合成苯丙炔酸甲酯的反应机理为研究对象，PhC=CH + CO + MeOH + 2NaOAc + 2CuCl（s）--> PhC=CCOOMe + 2AcOH + 2NaCl + 2CuCl（s）.我们最初对该反应的机理研究是基于非正式的（非计算机生成的）机理假设。当在20摄氏度和1个大气压下进行的实验使我们拒绝了五种可能的反应机理中的四种时，我们转向借助计算机程序ChemNet和MECHEM来制定新的假设，ChemNet生成了由233个基本步骤组成的反应网络，MECHEM从反应网络中发现了41条最简单的假设路径。我们随后对这41种假设机制的分析表明，基于CH 3OH/CH 3 OD动力学同位素效应的实验信息量很大。在非氘代和氘代甲醇中酯形成速率之间的比率接近于1，表明O-H键断裂发生在限速金属转移步骤CuC=CPh + PdCl 2--> ClPdC=CPh + CuCl之后。这个实验排除了32个不好的假设。根据初步实验研究的结果，又排除了四种机制。需要进一步开展工作，区分其余五个机制。(C)1998年Elsevier Science B.V.
We describe an experimental study of the reaction mechanism of phenylacetylene oxidative carbonylation to methyl ester of phenylpropiolic acid catalyzed by Pd(II) and Cu(I), PhC=CH + CO + MeOH + 2NaOAc + 2CuCl(s) --> PhC=CCOOMe + 2AcOH + 2NaCl + 2CuCl, which was closely guided by recent computational research on the generation of reaction mechanisms. Our initial mechanistic studies of this reaction were based on informal (non-computer-generated) mechanistic hypotheses. When experiments at 20 degrees C and 1 atm led us to reject four of five mechanistic possibilities for the reaction, we turned to formulating new hypotheses with the aid of the computer programs ChemNet, which generated a reaction network consisting of 233 elementary steps, and MECHEM, which uncovered 41 simplest hypothetical pathways from within the reaction network. Our subsequent analysis of these 41 hypothetical mechanisms suggested a highly informative experiment based on the CH3OH/CH3OD kinetic isotope effect. The ratio between the rates of ester formation in nondeuterated and deuterated methanol was close to unity, suggesting that O-H bond scission occurs after the rate-limiting transmetalation step CuC=CPh + PdCl2 --> ClPdC=CPh + CuCl. This experiment led to rejecting 32 out of the ill hypotheses. Four more mechanisms were rejected based on the results of preliminary experimental studies. Further work is needed to discriminate among the five remaining mechanisms. (C) 1998 Elsevier Science B.V.