Having demonstrated S-glycosidic Fdx derivatives to be more acid stable, we next wanted to extend the scope of Fdx thioglycosides. We envisioned our method for introducing S-based modifications to provide access for structural diversification. As per-O-acetylated 1-thioglucose 6a proved to be a suitable nucleophile in our procedure, we envisaged a two-step protocol for glycodiversification. Because separation of the acetylated regioisomers proved difficult, we opted to introduce per-O-acylated 1-thiosugars, followed by deprotection under basic methanolysis and finally separation via preparative RP-HPLC. We selected various per-Oacylated 1-thiosugars (6a-d, 9), comprising a hydrophilic CH2OAc unit, or hydrophobic methyl groups at C(5) of the pyranose. After full conversion of Fdx under LA conditions in the first reaction step, remaining LA was removed by an aqueous work-up to afford the acyl-protected thioglycoside derivatives along with side products from intramolecular reaction with the C(18)-OH. The acylated intermediates were then subjected to basic methanolysis to provide after separation the three regioisomeric products of the thioglycoside derivatives 18a-e (Fig. ).