Synthesis of glycocluster peptides

A new type of glycoconjugate mimetic is introduced that combines a glycocluster head group with a peptide part. These 'glycocluster peptides' are designed to serve as mimetics of glycocalyx constituents. A convergent synthetic scheme was followed, consisting of (i) the synthesis of a clustered carbohydrate head group carrying an amino acid at the focal point, and (ii) the solid phase synthesis of the peptide moiety. Finally, peptide coupling on resin furnished two prototype glycocluster peptides, which each exposes three alpha-mannosyl residues in the form of a dendritic wedge, with different conformational features. Extensive purification and NMR studies were necessary to characterize the target compounds and the results of these investigations are reported here together with the synthesis.