Pd Reaction Intermediates in Suzuki‐Miyaura Cross‐Coupling Characterized by Mass Spectrometry
Pd Reaction Intermediates in Suzuki‐Miyaura Cross‐Coupling Characterized by Mass Spectrometry
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铃木钯反应中间体——宫浦十字——质谱表征的耦合
DOI：
10.1002/cplu.202100545
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发表时间：
2022
期刊：
影响因子：
3.4
通讯作者：
Cooks, R. Graham
中科院分区：
文献类型：
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作者：
Chen, Xingshuo;Wei, Zhenwei;Huang, Kai‐Hung;Uehling, Mycah;Wleklinski, Michael;Krska, Shane;Makarov, Alexey A.;Nowak, Timothy;Cooks, R. Graham
钯催化的Suzuki-Miyaura（SM）偶联被广泛用于构建碳-碳键。在这项研究中，纳米电喷雾电离质谱（nanoESI-MS）应用于同时监测3-Br-5-Ph-吡啶和苯基硼酸的SM交叉偶联反应的预催化剂，催化中间体，试剂和产物。检测到与单配Pd（0）活性催化剂相关的一组Pd簇离子，并且其去卷积同位素分布揭示了来自两个中性分子的贡献。一个被分配给普遍接受的Pd（0）活性催化剂，在MS中被视为质子化分子，而另一个被暂时分配给氧化的催化剂，发现其随着反应进行而增加。使用FeCl 3进行的合成模型催化剂1，5-环辛二烯Pd XPhos（COD-Pd-XPhos）的氧化强制降解测试支持这一分配。在催化循环过程中的氧化加成中间体的形成和转化进行了监测，以提供有关金属转移步骤的进展信息。
Palladium‐catalyzed Suzuki‐Miyaura (SM) coupling is widely utilized in the construction of carbon‐carbon bonds. In this study, nanoelectrospray ionization mass spectrometry (nanoESI‐MS) is applied to simultaneously monitor precatalysts, catalytic intermediates, reagents, and products of the SM cross‐coupling reaction of 3‐Br‐5‐Ph‐pyridine and phenylboronic acid. A set of Pd cluster ions related to the monoligated Pd (0) active catalyst is detected, and its deconvoluted isotopic distribution reveals contributions from two neutral molecules. One is assigned to the generally accepted Pd(0) active catalyst, seen in MS as the protonated molecule, while the other is tentatively assigned to an oxidized catalyst which was found to increase as the reaction proceeds. Oxidative stress testing of a synthetic model catalyst 1,5‐cyclooctadiene Pd XPhos (COD−Pd‐XPhos) performed using FeCl3supported this assignment. The formation and conversion of the oxidative addition intermediate during the catalytic cycle was monitored to provide information on the progress of the transmetalation step.