Regiocontrolled Remote C-H Olefination of Small Heterocycles
Regiocontrolled Remote C-H Olefination of Small Heterocycles
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DOI：
10.1002/chem.201804351
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发表时间：
2018-12-05
影响因子：
4.3
通讯作者：
Maiti, Debabrata
中科院分区：
文献类型：
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作者：
Achar, Tapas Kumar;Ramakrishna, Kankanala;Maiti, Debabrata
实现芳烃的位点选择性C-H官能化是一个根本的挑战，因为它主要由分子的电子性质控制。螯合辅助的C-H官能化策略通过利用共价连接的导向基团（DG）的距离和几何形状克服了选择性问题。该策略需要化学计量的DG安装/移除和合适的官能团，在该官能团上拴系DG。这种策略对于小杂环是无效的，除非添加合适的官能团。此外，由于催化剂失活的可能性，杂环不是作为底物的明智选择。受最近发展的启发，这项工作表明利用螯合模板骨架承载共价连接的导向基团，这使得杂环的位点选择性远程C-H官能化。观察到的选择性是杂环和双官能模板骨架之间的非共价相互作用的结果。
Achieving site-selective C-H functionalization of arene is a fundamental challenge, as it is mainly controlled by the electronic nature of the molecules. A chelation-assisted C-H functionalization strategy overcomes the selectivity issues by utilizing distance and geometry of covalently attached directing groups (DGs). This strategy requires stoichiometric DG installation/removal and a suitable functional group on which to tether the DG. Such strategies are ineffective for small heterocycles unless suitable functional groups are added. Moreover, heterocycles are not the judicious choice as substrates owing to the possibilities of catalyst deactivation. Inspired by recent developments, this work demonstrates the utilization of a chelating template backbone bearing covalently attached directing groups, which enables site-selective remote C-H functionalization of heterocycles. The observed selectivity is the outcome of non-covalent interactions between the heterocycles and bifunctional template backbone.