Hydrolytic decomposition of glycosides in aqueous acids

A review is presented that collects the experimental results published on the acid catalyzed hydrolysis of alkyl and aryl pyranosides and furanosides over the last three decades. In aqueous acid, alkyl furanosides and pyranosides are hydrolysed via an oxocarbenium intermediate, which may be formed from the protonated substrate either by an exocyclic or endocyclic C-O bond cleavage. Both mechanisms lead eventually to the same products. Various methods have been used to distinguish between the pathways, and a lot of evidence exists to show that different pathways are followed depending on the structure of both the glycon moiety and the departing alcohol.