Advances in the Chemistry of Sulfur-Linked Glycosides: Focus on Functionalized 1-Thioglycosides

The synthesis of sulfur-linked glycosides, such as S-glycosides or S-glycoconjugates, has been extensively explored due to their roles as valuable tools in various biological studies. These compounds can act as glycosidase inhibitors, antibacterial agents, antitumor agents, and more. 1-Thioglycosides are characterized by a sulfur atom bonded to the anomeric position and are rare in nature. Besides their biological and pharmaceutical significance, thioglycosides serve as key substrates for the synthesis of other glycosides (O-, N-, and C-glycosides), glycoconjugates, glycoproteins, and polysaccharides. The growing interest in biologically active S-glycosides stems from their enhanced stability compared to O-glycosides, making them less prone to enzymatic hydrolysis and chemical degradation. This stability underpins their use as enzyme inhibitors and their presence in various drugs and bioactive natural products. Consequently, the development of efficient synthetic methodologies for functionalized 1-thioglycosides remains a critical focus in medicinal and organic chemistry research. This review focuses on recent advances in the synthetic methodologies for functionalized 1-thioglycosides, highlighting key strategies and their potential applications in medicinal chemistry.