Organofluorine compounds and fluorinating agents, 24 - Chiral perfluoroalkyl-substituted hexahydrofuro[2,3-b]pyran derivatives based on a carbohydrate precursor

(4'R)-4,6-Di-O-acetyl-1,2,3-trideoxy-3-iodo-4'-(2,2,3,3,4,4,5,5,6,6,7,7,8,8 ,9,9,9-heptadecafluorononyl)-2',3',4',5'-tetrahydro-alpha-D-glucopyranoso[1 ,2-b]furan (2) and its (4'S) diastereomer (3) were prepared by dithionite-m ediated addition of 1-iodoperfluorooctane to allyl 4,6-di-O-acetyl-2,3-dide oxy-alpha-D-erythro-hex-2-enopyranoside (radical "domino reaction"); Subseq uently, the major product [(4'R) form] was deprotected via 4 to the hexahyd rofuro[2,3-b]pyran derivative 5, which was used as a fluorinated building b lock to: prepare the nonamphiphilic chiral mesogens 6-8 by "Mitsunobu" ethe rification and 9 by esterification. The reagents-used to transform 5 to 6-9 were 4-cyanophenol, 4-(4-cyanophenyl)phenol, 4-(4-heptyloxybenzoyloxy)phen ol, and 4-heptyloxybenzoyl chloride.