Stereoselective synthesis of 2,3-unsaturated 1,6-oligosaccharides by means of a glycal-derived allyl epoxide and N-nosyl aziridine.

beta-D-threo- and 4-deoxy-4-amino-alpha-D-erythro-hex-2-enopyranosyl di- (n = 0) and trisaccharides (n = 1) of types A and B were synthetized by means of a reiterative, completely stereoselective glycosylation process which makes use of the D-galactal-derived allyl epoxide 1 beta and D-allal-derived allyl N-nosyl aziridine 2 alpha, respectively.