Thioglycosides were first reported in 1909 by Fischer and since then have been explored constantly allowing for the development of numerous protocols for their preparation.
The advantage of using thioglycosides is their stability under a wide range of reaction conditions allowing for protecting group manipulations.  Additionally thioglycosides act as temporary protecting groups at the anomeric position allowing for thioglycosides to be useful as both glycosyl donors as well as glycosyl acceptors.
Thioglycosides are usually prepared by reacting per-acetylated sugars with  and the appropriate thiol.
Thioglycosides used in glycosylation reactions as donors can be activated under a wide range of conditions, most notably using NIS/AgOTf.