硫醚作为一类重要的含硫功能分子，广泛存在于天然产物、药物及有机发光材料中。鉴于硫醚类化合物的重要性，近年来化学家们发展了一系列高效构建硫醚的方法。与传统的有机卤化物/有机硼酸与硫醇交叉偶联的合成方法相比，C―H官能化直接构建硫醚的策略因其步骤经济性、原子经济性备受合成化学家们关注，并取得重要进展。本文根据不同过渡金属进行分类，系统阐述了近年来过渡金属催化/参与C―H官能化或无过渡金属催化C―H官能化构建硫醚这一方向研究进展。
Thioesters, which are essential sulfur-containing organic molecules, are indispensable in natural products, pharmaceuticals, and organic light-emitting materials. Efficient synthesis of thioethers has received considerable attention due to the widespread applications of these compounds, and many fundamental approaches for C―S bond formation have been proposed. However, most of them construct C―S bonds by employing organic halides/organic boronic acid. These methodologies generally suffer from a pre-functionalized starting material. Recently, selective C―H functionalization emerged as a powerful tool for the synthesis of C―N, C―O, C―C, and C-halogen bonds. Nevertheless, C―S bond formation via C―H functionalization has only recently been given more importance because organosulfur compounds are believed to inactivate catalysts. In contrast to traditional cross-coupling reactions, direct functionalization of C―H bonds for the synthesis of thioethers can shorten the reaction steps and minimize the amount of waste formed. In this review, which is divided into several parts, we describe C―H functionalization strategies for the construction of thioethers. In Part Ⅰ, we introduce the importance and widespread applications of thioethers in daily life. For example, Lissoclibadin 6 is a polysulfur aromatic alkaloid that shows antimicrobial activity. Seroquel is an antipsychotic medicine. It is used to treat bipolar disorder and schizophrenia in adults, and children who are at least 10 years old. Tazarotene is approved for the treatment of psoriasis, acne, and sun-damaged skin. Furthermore, a comparison between conventional synthesis methods and C―H thiolation is discussed. In Part Ⅱ, we introduce copper-catalyzed or copper-mediated C―H thiolation. Along with the direct functionalization of sp2 and sp C―H for the synthesis of aryl sulfides, some significant and challenging thiolations of sp3 C―H are included. In addition to copper, palladium is an excellent catalyst for C―H functionalization. In Part Ⅲ, we elucidate palladium-catalyzed C―H thiolation and discuss many proposed mechanisms. Nickel, which is a first-flow, low-cost, and earth-abundant metal catalyst, has increasingly gained attention. In contrast to copper and palladium, despite its late start, several remarkable reports on nickel-catalyzed C―H thiolation were published by several groups.