Synthesis of a hybrid type N-glycan heptasaccharide oxazoline for Endo M catalysed glycosylation

•Convergent synthesis of a hybrid type N-glycan heptasaccharide.•Global de-protection by Birch reduction.•Oxazoline formation in water.•Endo M catalysed glycosylation of a GlcNAc-Asn glycosyl amino acid.

Endo-β-N-acetylglucosaminidases (ENGases) are versatile biocatalysts that allow access to a wide variety of defined homogenous N-linked glycoconjugates in a convergent manner. A hybrid-type N-glycan was accessed by total synthesis, converted to an oxazoline, and used as a donor substrate with both wild type Endo M and an N175Q glycosynthase Endo M mutant allowing the convergent synthesis of a glycosylated amino acid bearing a hybrid N-glycan structure.

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