Stereoselective Synthesis of α‐3‐Deoxy‐<scp>D</scp>‐<i>manno</i>‐oct‐2‐ulosonic Acid (α‐Kdo) Glycosides Using 5,7‐<i>O</i>‐Di‐<i>tert</i>‐butylsilylene‐Protected Kdo Ethyl Thioglycoside Donors

Abstract

An efficient methodology for the synthesis of α-Kdo glycosidic bonds has been developed with 5,7-O-di-tert-butylsilylene (DTBS) protected Kdo ethyl thioglycosides as glycosyl donors. The approach permits a wide scope of acceptors to be used, thus affording biologically significant Kdo glycosides in good to excellent chemical yields with complete α-selectivity. The synthetic utility of an orthogonally protected Kdo donor has been demonstrated by concise preparation of two α-Kdo-containing oligosaccharides.