Transition Metal-Catalyzed C-H Bond Functionalizations by Use of Sulfur-Containing Directing Groups

Transition metal-catalyzed direct functionalization of C-H bonds is an economical and efficient way to construct complex molecules that is currently attracting tremendous attention. In particular, the strategy involving transition metal-catalyzed regioselective C-H activation assisted by sulfur-containing directing groups has been realized in the past few years in spite of sulfur's ability to poison many transition metal catalysts. This review describes the rational development of sulfur-containing directing groups including thioethers, sulfoxides, thioamides, alkoxythiocarbonyl groups, and thioketones. Through collective efforts in the community, a range of transition metal-catalyzed C-H activation transformations using this type of directing group has been developed.