A new approach to the neoglycopeptides: synthesis of urea- and carbamate-tethered N-acetyl-D-glucosamine amino acid conjugates.

A novel approach to the synthesis of Fmoc-protected neoglycopeptide building blocks is described. Oxidation of N-acetyl-D-glucosamine isonitrile afforded the corresponding highly reactive glycopyranosyl isocyanate, which reacted with amino acid derivatives to furnish the corresponding urea- and carbamate-tethered Fmoc-protected N-acetyl-D-glucosamine amino acid conjugates in good yields. [reaction: see text]