The stereoselectivity of the 1, 2-trans directed, Lewis acid-catalysed azidation of peracylated furanoses was found to depend on the reactivity of the azide donor (azide nucleophilicity) and the configuration at the anomeric centre relative to the neighbouring 2-O-acyl group. Reactions of 1, 2-trans glycosyl esters with highly nucleophilic azide donors, generated from SnCl4 and Me3SiN3, were stereospecific. The results are interpreted in terms of the rapid ...
