Synthesis of pseudaminic acid, a unique nonulopyranoside derived from pathogenic bacteria through 6-deoxy-AltdiNAc

Chemical synthesis of pseudaminic acid is described. Starting from N-acetylglucosamine, deoxygenation and deoxyamination with stereo-inversion afforded 6-deoxy-AltdiNAc, which is the key intermediate for the biosynthesis of pseudaminic acid. Subsequently, the elongation reaction via In-mediated allylation of 6-deoxy-AltdiNAc with bromomethacrylate ester derivative followed by ozonolysis and hydrolysis gave the desired pseudaminic acid. Furthermore, we demonstrated glycosylation with dibenzyl phosphite derivative of pseudaminic acid as the glycosyl donor to afford disaccharide.