Reported herein is a Pd-catalyzed regioselective C–H activation method that is used for C–H deuteration, carbonylation, halogenation, and oxidation of arene substrates substituted by two N-heterocycles. When conducted in acetic acid (AcOH), these reactions occur at the five-membered palladacycle sites, whereas they switch to the six-membered palladacycle sites in trifluoroacetic acid (TFA). This controllable regioselective C–H activation is applied for late-stage functionalization of bioactive molecules. A mechanism study indicated that the regioselectivity is achieved by Brönsted acid–Lewis base interactions and electronic effects (in TFA) and the different kinetic stabilities of palladacycle intermediates (in AcOH).

中文翻译：

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钯催化的两个N-杂环取代的芳烃的区域选择性C–H功能化及其在后期功能化中的应用

本文报道了一种钯催化的区域选择性C–H活化方法，用于C–H氘代，羰基化，卤化和氧化被两个N-杂环取代的芳烃底物。当在乙酸（AcOH）中进行时，这些反应发生在五元的Palladacycle位置，而它们切换到三氟乙酸（TFA）中的六元的Palladacycle位置。这种可控的区域选择性C–H激活被用于生物活性分子的后期功能化。一项机理研究表明，区域选择性是通过布朗斯台德酸-刘易斯碱相互作用和电子效应（在TFA中）以及palladacycle中间体的不同动力学稳定性（在AcOH中）实现的。