Facile Synthesis of a β(1‐3)‐Linked gal‐galactal Disaccharide and Its Use in N‐Iodosuccinimide‐Activated O‐Glycopeptide Synthesis

The fact that compound 1 can now be synthesized in four steps with an overall yield of 21 % should ensure its broader utilization in the NIS-activated synthesis of glycopeptides. The key intermediate in the process is the selectively protected galactaldehyde derivative 2.1 reacts not only with the universally applicable Fmoc-Ser-OBzl subunit but also with a cyclic glycophorin-A fragment.