Access to 3-O-Functionalized N-Acetylneuraminic Acid Scaffolds.

Direct access to 3-O-functionalized 2-α-N-acetylneuraminides and their corresponding 2,3-dehydro-2-deoxy-N-acetylneuraminic acid derivatives is described. Initially, a stereoselective ring-opening of the key intermediate N-acetylneuraminic acid (Neu5Ac) 2,3-β-epoxide with an alcohol provided the 3-hydroxy α-glycoside. O-Alkylation of the C3 hydroxyl group generated novel 3-O-functionalized Neu5Ac derivatives that provided the corresponding unsaturated derivatives upon elimination.