Glycosyl donor
![A series of common glycosyl donor types. All are very reactive when activated with a promoter or catalyst: The bromide can be activated by silver salts, the trichloroacetimidate with acid catalysis, and thioglycosides with N-iodosuccinimide/triflic acid. The reactivity of glycosyl donors depend very much on their protection groups, which led to classification of these compounds into three categories of reactivity: Disarmed, armed, and superarmed.](/Images/godic/202501/15/lossy-page1-900px-Glycosyl_donors_1.tif0852.jpg")
A glycosyl donor is a carbohydrate mono- or oligosaccharide that will react with a suitable glycosyl acceptor to form a new glycosidic bond. By convention, the donor is the member of this pair that contains the resulting anomeric carbon of the new glycosidic bond. The resulting reaction is referred to as a glycosylation or chemical glycosylation.