Tandem One-Pot Acetalation-Acetylation for Direct Access to Differentially Protected Thioglycosides and O-Glycosides with p-Toluenesulfonic Acid

摘要: A new tandem one-pot acetalation-acetylation proce- dure is reported which streamlines routine protecting-group manip- ulation of carbohydrate molecules in production differentially protected O- and thioglycosides. This procedure eliminates the use highly toxic pyridine, p-toluenesulfonic acid employed as catalyst for acetalation acetylation. Synthetic utility demonstrated expeditious preparation glycosides from a wide variety carbohy- drate substrates including unprotected O-glycosides, thioglyco- sides, N-acetyl neuraminic ester.