Syntheses of some polyfluoro-aromatic derivatives of carbohydrates and polyols

Abstract

The reactions of partially substituted carbohydrates and polyols. e.g. 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose (1), 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose (3), and 1,2:5,6-di-O-isopropylidene-D-mannitol (8) with sodium hydride followed by hexafluorobenzene in 1,2-dimethoxyethane yield the corresponding pentafluorophenyl ethers. Monoethers can be prepared from diols and these compounds on treatment with sodium hydride yield novel cyclic carbohydrate derivatives, e.g. methyl 4,6-O-benzylidene-2,3-O-(tetrafluoro-o-phenylene)-α-D-glucopyranoside (16). Reaction of the alkoxide of compound (3) with its 6-O-pentafluorophenyl ether (4) links the two sugar residues through the aryl nucleus. Arylation of 1,2-O-isopropylidene-α-D-glucofuranose (20) yields, besides the expected 1,2-O-isopropylidene-3,5,6-tri-O-pentafluorophenyl-α-D-glucofuranose (21), a second product. 1,2-O-isopropylidene-6-O-pentafluorophenyl-3,5-O-(tetrafluoro-o-phenylene)-α-D-glucofuranose (22).