Synthesis of C-glycosides enabled by palladium-catalyzed glycosylation reactions

C-Glycosides are a privileged class of carbohydrates that exhibit remarkable biological and pharmaceutical activities. Transition metal-catalyzed cross-coupling reactions are powerful tools for the efficient and rapid construction of C-C bonds. Among various transition-metal catalyzed methods, palladium-catalyzed C-glycosylation is an effective and reliable approach to synthesize C-glycosides and involves the reaction of glycosyl donors and various reaction partners via C-C glycosidic bond formation under mild conditions with high regio/stereo-selectivities. In this review, palladium-catalyzed C-glycosylation reactions from 2020 to 2024 are summarized and discussed in detail, with focus on the synthesis of C-aryl glycosides, C-alkyl glycosides, C-alkenyl glycosides, and other functionalized C-glycosides. Some representative synthetic strategies and their transformation application along with reaction mechanisms are also highlighted.