Hydrogen fluoride-catalyzed formation of glycosides. Preparation of methyl 2-acetamido-2-deoxy-β-d-gluco- and -β-d-galacto-pyranosides, and of β-(1→6)-linked 2-acetamido-2-deoxy-d-gluco- and -d-galacto-pyranosyl oligosaccharides
Dissolution of 2-acetamido-2-deoxy-d-glucose (1) or -d-galactose (2) in anhydrous hydrogen fluoride, followed by addition of methanol, gave stereospecifically the corresponding methyl β-d-glycopyranosides 7 and 8. When solutions of 1 or 2 in hydrogen fluoride were slowly evaporated, mixtures of exclusively β-d-(1→6)-linked di- to hexa-saccharides containing 2-acetamido-2-deoxy-glucosyl (9) and -galactosyl