Methods for synthesizing Salacinol, its stereoisomers, and analogues, homologues and other derivatives thereof potentially useful as glycosidase inhibitors. In some embodiments the compounds of the invention may have the general formula (I) or (II): The synthetic schemes may comprise reacting a cyclic sulfate with a 5-membered ring sugar containing a heteroatom (X). The heteroatom preferably comprises sulfur, selenium, or nitrogen. The cyclic sulfate and ring sugar reagents may be readily prepared from carbohydrate precursors, such as D-glucose, L-glucose, D-xylose and L-xylose. The target compounds are prepared by opening of the cyclic sulfates by nucleophilic attack of the heteroatoms on the 5-membered ring sugars. The resulting heterocyclic compounds have a stable, inner salt structure comprising a heteroatom cation and a sulfate anion. The synthetic schemes yield various stereoisomers of the target compounds.