1-C-(20-Oxoalkyl)-5-azido-5-deoxy-glycofuranosides were used as latent substrates for intramolecular hetero-Michael addition. Reduction of the azido groups by catalytic hydrogenation followed by base treatment produced 20-ester and 20-ketone aza-Cglycopyranosides. The conjugation addition was stereoselective in favor of aza-C-glycosides with equatorial substitutions at the pseudo anomeric center