Stereoselective synthesis and sialidase inhibition properties of KDO-based glycosyloxathiins

The stereoselective synthesis of KDO-based glyco-1,4-oxathiins, obtained by totally diastereoselective inverse electron demand hetero Diels-Alder, αα′-dioxothiones as electron-poor heterodienes, and glycals as electron-rich dienophiles, is described.The synthetic and biological data reported confirmed the versatility of this powerful [4+2] cycloaddition and showed the KDO-based cycloadduct as attractive scaffold for the development of new sialidase inhibitors.