Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Science. 2021 May 14;372(6543). doi: 10.1126/science.abd5992.
Transition metal-catalyzed aryl C-H activation is a powerful synthetic tool as it offers step and atom-economical routes to site-selective functionalization. Compared with proximal -C-H activation, distal (- and/or -) C-H activation remains more challenging due to the inaccessibility of these sites in the formation of energetically favorable organometallic pretransition states. Directing the catalyst toward the distal C-H bonds requires judicious template engineering and catalyst design, as well as prudent choice of ligands. This review aims to summarize the recent elegant discoveries exploiting directing group assistance, transient mediators or traceless directors, noncovalent interactions, and catalyst and/or ligand selection to control distal C-H activation.
过渡金属催化的芳基 C-H 活化是一种强大的合成工具，因为它提供了具有步骤经济性和原子经济性的方法，可实现选择性功能化。与近位 -C-H 活化相比，由于在形成有利的有机金属预过渡态时这些位置不易接近，因此远距离 (- 和/或 -) C-H 活化仍然更具挑战性。将催化剂引导至远程 C-H 键需要明智的模板工程和催化剂设计，以及配体的谨慎选择。本综述旨在总结最近利用导向基团辅助、瞬态介体或无痕迹导向剂、非共价相互作用以及催化剂和/或配体选择来控制远程 C-H 活化的优雅发现。
