过渡金属催化的区域选择性芳烃C—H键氧化生成C—O键（英文）

Transition Metal-Catalyzed Regio-selective Aromatic C—H Bond Oxidation for C—O Bond Formation

近年来过渡金属催化的芳烃直接C—H氧化反应取得了重要进展,该策略被用于多种酚类化合物的制备.反应体系使用的过渡金属催化剂包括钯、铜、钌、铱等;氧化剂包括高价碘化合物、过硫酸盐、氧气等.此前已有多篇综述就特定的过渡金属或氧化剂参与的C—H氧化反应进行了详尽的讨论.本综述着重探讨过渡金属催化的邻、间、对位选择性的芳烃C—H氧化反应,并试图阐释上述区域选择性的产生机制,其中包括导向基团的螯合辅助作用、配体控制、底物自身因素等.在讨论部分提出了过渡金属催化的芳烃C—H氧化反应中存在的问题以及影响该策略发展应用的可能限制因素.

Recent years the great progress in transition metal-catalyzed direct aromatic C—H oxidation has been witnessed, which has been utilized in the preparation of various phenolic compounds. These transformations employ inter alia palladium, copper, ruthenium, iridium, etc. as the transition metal catalysts, and hypervalent iodine, persulfate, or oxygen as the oxidants. There have been several reviews in which the C—H oxidations with specific transition metal or oxidant was discussed. This review focuses specifically on transition metal-catalyzed aromatic C—H oxidations with ortho-, meta-, or para-selectivity, and rationalizes the possible generation mechanism of regio-selectivities, which might be controlled by the directing group via chelation-assistance, the ligand, or intrinsic properties of the substrate. The discussion section indicated the existing problems of transition metal-catalyzed aromatic C—H oxidations, as well as the possible limiting factors for the development and application of this strategy.