Yang Jiong
Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA.
Org Biomol Chem. 2015 Feb 21;13(7):1930-41. doi: 10.1039/c4ob02171a.
Direct functionalization of C-H bonds represents a powerful strategy for the synthesis of complex organic compounds due to its inherent efficiency. Among various approaches, transition metal catalyzed direct activation of unreactive C-H bonds is particularly effective for this purpose. However, the development of practical methods for transition metal catalyzed direct C-H functionalization has been challenging. Apart from identifying the reaction conditions that allow the activation of relatively unreactive C-H bonds, these reactions need to be selective, allowing one C-H bond to be differentiated from the rest of the ubiquitous C-H bonds of the compound. Whereas directing group guided, transition metal catalyzed ortho-C-H functionalization of aromatic compounds has seen significant growth in the past few decades, methods for meta-C-H functionalization of arenes have also emerged. This review summarizes approaches for directing group guided, transition metal catalyzed meta-C-H functionalization of aromatic compounds. Some steric-controlled, transition metal catalyzed formal meta-C-H functionalization reactions without coordinating directing groups are also discussed.
由于其固有的高效性，C-H键的直接官能团化是合成复杂有机化合物的一种强大策略。在各种方法中，过渡金属催化的未反应C-H键的直接活化对于此目的特别有效。然而，开发用于过渡金属催化的直接C-H官能团化的实用方法一直具有挑战性。除了确定允许相对未反应的C-H键活化的反应条件外，这些反应还需要具有选择性，使得一个C-H键能够与化合物中普遍存在的其他C-H键区分开来。尽管在过去几十年中，导向基团引导的过渡金属催化的芳香族化合物邻位C-H官能团化有了显著发展，但芳烃间位C-H官能团化的方法也已出现。本综述总结了导向基团引导的过渡金属催化的芳香族化合物间位C-H官能团化的方法。还讨论了一些空间控制的、无配位导向基团的过渡金属催化的形式间位C-H官能团化反应。
