Synthesis of thiofuranosides by dehydrative glycosylation in micellar media

Abstract

Green and aqueous-based dehydrative glycosylation of thiofuranosides in micellar media was developed. The thiofuranosides are useful as precursors for carbohydrate synthesis, biological active molecules, and bio-surfactants. Dodecylbenzenesulfonic acid (DBSA), a commercially available Brønsted acid-surfactant, was employed to increase solubility of substrates and enhance rate of the glycosylation. Herein, we report the dehydrative glycosylation of furanosides and pyranosides with aliphatic, aromatic, and heterocyclic thiols in aqueous media to afford the thiofuranosides. Microwave irradiation led to improved yields and shorter reaction times. Other reaction parameters such as temperature and the amount of acid used were also optimized. Aliphatic and aromatic thiofuranosides were prepared from lactol precursors in moderate yields (24–72%) when using 100 mol% DBSA. Noteworthy, the open-chain dithioacetal which is a common by-product from the dehydrative glycosylation was not detected under these reaction conditions. Moreover, the methodology was simple and convenient to set up without the requirement for anhydrous conditions.