Highly alpha-selective sialyl phosphate donors for efficient preparation of natural sialosides

Article abstract of DOI:10.1002/chem.200903035

A new sialylation reagent that employs an N-acetyl-5-N,4-O-carbonyl protection with dibutyl phosphate as the leaving group has been reported. N-Acetyl neuraminic acid (Neu5Ac) is most frequently found at the terminal end of glycoconjugates on the cell surface. The ring-opening product was obtained as the major product in the hydrolytic step. The one-pot synthetic operation was performed in the presence of NIS/trifluoromethanesulfonic acid (TfOH) promoter system. The sialyl phosphate donor also can be used in an orthogonal one-pot glycosylation, providing an alternative choice for the rapid synthesis of sialosides, allowing the coupling of building blocks independent of their relative reactivities, such as SSEA-4. Sialyl phosphate donors are very efficient at creating complex natural sialosides and are being used for rapid preparation of important sialoside microarrays.