A novel synthetic approach to construct various 3,6-anhydrohexosides via an intramolecular cyclization of corresponding triflates is described. The nucleophilic attack from C3 p-methoxybenzylated hydroxyl to C6 trifluoromethanesulfonate on triflate structures triggered the cyclization reaction to provide 3,6-anhydrohexosides in excellent yields, making the strategy more efficient with respect to the reported protocols. By applying this methodology, a concise first total synthesis of natural product isolated from leaves of Sauropus rostratus was accomplished.

Coupling reaction between thiosugar and triflate as the key protocol to synthesize neoponkoranol, a naturally occurring potent α-glucosidase inhibitor, and its related sulfonium salts was optimized by applying different esters as protecting group, with the yields of desired products being greatly improved. Our proposed mechanism of the coupling reaction indicated that the nucleophilicity of C3-hydroxyl moiety on monosaccharide structure is closely related to the reaction mode.

The first total synthesis of four 2-deoxy-3,6-anhydro hexofuranoside derivatives, namely sauropunols (A–D), isolated from the traditional Chinese medicinal plant Sauropus rostratus was accomplished. Structures of sauropunols A and B were clearly elucidated and reassigned. The anti-inflammatory activities of sauropunols (A–D) as well as the synthetic intermediates were evaluated, which is valuable for further structure–activity relationship (SAR) studies on this class of natural products.