beta-acarbose. VII - Approaches towards the synthesis of some N-linked carba-oligosaccharides

3,4-Anhydro-1,6-dideoxy-1,6-episeleno-beta-D-glucose was treated with cyclo hexylamine to afford an amino diol which was subsequently converted into a cyclic carbamate, a compound shown to be a moderately successful glycosyl d onor. Treatment of the same 3,4-anhydro sugar and the 1,6-epithio analogue with a 1-epivalienamine derivative afforded the corresponding secondary ami nes which were converted into the analogous cyclic carbamates. The epithio analogue was unsuccessful as a glycosyl donor, failing to glycosylate a car bohydrate alcohol. On the other hand, the episeleno compound appeared to fu nction as a glycosyl donor but decomposition of the product occurred under the conditions necessary for its isolation.