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本文运用密度泛函理论(DFT)计算研究了以Togni试剂为氟源,CuI/邻二氮菲催化的芳基硼酸三氟甲基化反应机理.计算结果表明,该反应经历转金属化-协同亲电取代路径,通过协同的五元环过渡态亲电取代过程实现三氟甲基转移.反应势能面分析显示,芳基硼酸与铜催化剂的转金属化是整个反应路径的决速步,其活化能是21.7 kcal/mol.在此基础上,对比计算了苯乙基硼酸与铜催化剂的转金属化过程,研究结果表明,与苯基硼酸相比,烷基硼酸的转金属化的能垒更高,是动力学不利的过程.
In this paper, the mechanism of trifluoromethylation of arylboronic acid catalyzed by Togni reagent as a fluorine source and CuI / phenanthroline was studied by using density functional theory (DFT). The calculated results show that the reaction undergoes metallization-coordination Electrophilic substitution pathways, through the coordinated five-membered ring transition state electrophilic substitution process to achieve trifluoromethyl transfer reaction potential surface analysis shows that the transition metal aryl boronic acid and copper catalyst is the pace of the entire reaction path step The activation energy is 21.7 kcal / mol. On this basis, the transmetallation of p-ethylboronic acid with copper catalyst was calculated. The results show that compared with phenylboronic acid, the transmetallic energy barrier Higher, is a kinetic unfavorable process.