Synthesis of a LEC14 nonasaccharide, a core-fucosylated, biantennary N-glycan with a novel GlcNAc residue in the core region

The recently found core substitution of N-glycans termed LEC14 is characterized by a GlcNAc residue linked β(1,2) to the central β-mannoside. Starting from a pentasaccharide building block functionalized for core-fucosylated N-glycans the total synthesis of a protected LEC14 nonasaccharide was accomplished. The key step of the synthesis was the introduction of the additional β(1,2)-linked GlcNAc residue that was highly dependent on the solvent and appears to proceed via an amide acetal intermediate.