C-5 modifications in N-acetyl-neuraminic acid: scope and limitations.

Glycoconjugates containing sialic acid are involved in a large variety of biological phenomena, including cell-cell adhesion, recognition by viruses and bacteria, and oncogenesis. Therefore, they are important synthetic targets for the design of drugs and vaccines. In the last decades, different methodologies that improve yield and stereoselectivity in sialylation reactions have been investigated. This review summarizes the latest developments in the synthesis of C-5 modified sialic acid glycosyl donors and glycosyl acceptors and their application in the synthesis of alpha-sialosides.