Recent Advances in Visible-Light-Catalyzed C—C Bonds and C—Heteroatom Bonds Formation Using Sulfonium Salts
Hao Xu, Jie Zhang, Junze Zuo, Fengxiao Wang, Jian Lü, Xu Hun, Daoshan Yang
Abstract
Sulfonium salts are one of the most important class of organosulfur (IV) compounds which have a positive charge on the sulfur center with three C-S bonds.Because of their bench-stable, easy synthesis, broad structural diversity, and rich reactivity, sulfonium salts are playing a significant role in synthetic chemistry.In recent years, visible-light promoted photoredox catalysis is rapidly developing into a powerful tool for organic synthesis.In this paper, the recent advances of different sulfonium salts in the radical type reactions induced by visible light are summarized.The formation reactions of C-C bond and C-X (X＝B, N, O, S, Se, Te, F, Cl, I) bonds are introduced, and the applicable scope and mechanism of some reactions are also discussed.Keywords sulfur chemistry; sulfonium salt; visible light; free radical reaction 有机硫化合物在合成化学、生物医学和功能有机材 料领域扮演着极其重要的角色 [1] .据统计结果显示, 美 国销量排名前 200 位的药品中, 有 24.8%含有硫元素 [2] .硫原子与同族的氧原子相比, 其半径更大、电负性更低, 使得硫的外电子层更易于接受或提供电子, 显示出独特 的反应活性, 而硫鎓盐是中心硫原子与三个取代基相连 的带正电的有机硫化合物(通式为[R 3 S] ＋ X -).与同族氧 鎓盐相比, 硫鎓盐结构更加多样、热力学稳定性更强、 更易于合成、后处理更加简便 [3] .常见的硫鎓盐的合成方法如 Scheme 1 所示 [4] : (a)通 过二卤代烃与硫醇的亲核取代反应, 该方法制备硫鎓盐 操作简便, 结晶度好且稳定性高, 但主要局限于五元环 和六元环状硫鎓盐的制备.(b)采用硫醚和烷基卤化物通 过分子间亲核取代反应制备硫鎓盐, 该方法是目前应用 有机化学