N-Acetyl neuraminic acid (Neu5Ac) is most frequently found at the terminal end of glycoconjugates on the cell surface. This terminally exposed position allows Neu5Ac- containing conjugates to be exploited as receptors for viruses and bacteria, in addition to governing a wide variety of biological processes, such as tumor metastasis, cell differentiation, and cell–cell interactions.[1] In naturally occurring sialosides, Neu5Ac is ...