Zinc chloride aryl glycosides, preparation

Aryl glycosides of 2-amino-2-deoxy sugars, as might be expected, can be prepared by similar techniques as was illustrated by the synthesis of phenyl 3,4,6-tri-0-acetyl-2-acetamido-2-deoxy-p-D-glucoside and -D-galactoside by toluene -sulphonic acid catalysed reactions between phenol and the hexosamine penta-acetates These products were then anomerised using zinc chloride as catalyst to provide means of obtaining -anomers. 

Silver imidazolate together with mercury(II) chloride or zinc(II) chloride has proved to an efficient promoting system for glycosidations. For example, l,2-(ra/w-linked aryl glucosides have been prepared from fully acetylated glycopyranosyl bromides in almost quantitative yield (equation 6).7(5... 

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