A Facile Synthesis of N^γ-Glycosyl Asparagine Conjugates and Short N-Linked Glycopeptides

Abstract

Both free and protected glycosyl azides were efficiently coupled to the side chain of aspartate by the Staudinger reaction for the synthesis of N ^γ-glycosyl asparagine conjugates and short N-linked glycopeptides that can be employed to construct complex N-linked glycopeptides. In the process, a facile two-step protocol was developed for free glycosyl azide synthesis, which includes reported direct transformation of free oligosaccharides into glycosyl amines through reaction with ammonium bicarbonate and then stereospecific diazo transfer reaction to convert glycosyl amines to glycosyl azides.

Keywords:

• Glycosyl asparagine
• Glycopeptide
• Glycosyl azide
• Thioester
• Staudinger reaction

ACKNOWLEDGEMENT

We thank Mizutani Foundation for Glycoscience, Japan, and NSF, USA (CHE-10538480), for the research awards to support this work.