N-Glycoside neoglycotrimers from 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl azide

2,3,4,6-Tetra-O-acetyl-β-d-glucopyranosyl azide is available on large scale from d-glucose by means of a three-step sequence involving acetylation, activation as the glycosyl bromide, and stereospecific displacement with azide anion. The azide functionality then serves as a convenient anchor upon which to introduce new functionality, usually with retention of the β-stereochemistry. Here we report the synthesis of an amide-linked N-glycosyl trimer, by employing a Staudinger–aza-Wittig process on the azide, as well as a hybrid N-glycosyl triazole–amide-linked trimer in which the sugars are separated by 1,2,3-triazole heterocycles. Both of these neoglycotrimers are isolated in good yield with high β-selectivity in each case.

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