Synthesis of N‐Glycopeptide Clusters with Lewisx Antigen Side Chains and Their Coupling to Carrier Proteins

As a tumor-associated cell-antigen mimic, Lewisx trisaccharide determinant 1 was constructed with the azide function as anomeric protecting group with the aid of a 4-Mpm-protected (Mpm = methoxyphenylmethyl) fucosyl donor. Exchange of the OMpm functions for OAc groups furnishes a Lewisx trisaccharide stable enough against acid attack for glycopeptide synthesis. A glycopeptide with two Lewisx antigen side chains was deblocked and coupled to bovine serum albumin as well as to KLH (keyhole limpet hemocyanin). These synthetic glycoproteins simulate biantennary Lewisx antigen structures.