Iridium‐catalysed C‐H Borylation of Fluoroarenes: Insights into the Balance between Steric and Electronic Control of Regioselectivity
Iridium‐catalysed C‐H Borylation of Fluoroarenes: Insights into the Balance between Steric and Electronic Control of Regioselectivity
复制标题
铱催化氟芳烃的 C-H 硼化：深入了解区域选择性的空间和电子控制之间的平衡
DOI：
10.1002/ejoc.202201005
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发表时间：
2022
影响因子：
2.8
通讯作者：
P. Steel
中科院分区：
文献类型：
--
作者：
M. Ding;J. A. Reuven;Andrew C. Hones;M. A. Fox;P. Steel
铱催化的多氟芳烃和杂芳烃的C-H硼基化反应快速有效地发生。与其他硼化反应一样，虽然空间参数占主导地位，但可以观察到对反应选择性的潜在电子影响。值得注意的是，氟化（杂）芳烃中的硼基化区域选择性由纯电子效应决定，除了两个氟原子之间的邻硼基化，其中氟取代基的空间效应变得明显。硼化在theparposition相对于氟是不利的，而硼化paraparto吡啶的连氮基氮观察到一个强大的电子偏好。当这些特征配合时，可以预期高选择性。对于这些反应，计算过渡态的基础上，而不是中间体，铱的几何形状的能量表现出良好的预测和观察到的选择性之间的协议。
The iridium catalysed C−H borylation of polyfluorinated arenes and heteroarenes occurs rapidly and efficiently. As with other borylation reactions, whilst steric parameters dominate, an underlying electronic influence on reaction selectivity can be observed. Notably borylation regioselectivity in fluorinated (hetero)arenes is determined by purely electronic effects except forortho‐borylation between two fluorine atoms where steric effects of fluorine substituents become apparent. Borylation at theparaposition with respect to fluorine is disfavoured whereas a strong electronic preference for borylationparato the azinyl nitrogen of pyridine is observed. When these features co‐operate high selectivity can be expected. For these reactions, computations based on transition state, rather than intermediate, energies in iridium geometries showed excellent agreement between predicted and observed selectivities.