N-Nosyl as a stereoselectivity-improving and easily removable group in the O-glycosylation of D-allal and D-galactal-derived allyl aziridines. Stereospecific synthesis of 4-amino-2,3-unsaturated-O-glycosides

The stereospecific O-glycosylation of alcs., phenol, and partially protected monosaccharides with the diastereoisomeric D-allal and D-galactal-derived N-nosyl aziridines I and II leads to the corresponding 4-N-(nosylamino)-2,3-unsatd.-α-O-glycosides, e.g. III (R1 = OMe, R2 = H), and β-O-glycosides, e.g. III (R1 = H, R2 = OMe), resp.  The N-(nosylamino) group of 4-N-(nosylamino)-2,3-unsatd.-α-O- and β-O-glycosides can easily be deprotected to give the corresponding 4-amino-2,3-unsatd.-O-glycosides.