ORGANOFLUORINE COMPOUNDS AND FLUORINATING AGENTS .9. FROM GLYCOSYL FLUORIDES TO CHIRAL CROWN-ETHERS

Methyl D-galactofuranoside (1), methyl D-glucofuranoside (3), 3-O-subs tituted 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranoses (5a-g), opy lidene-3,5,6-tri-O-methyl-alpha-D-glucofuranose (7) as well as the tra ns-decalin analog ethanediyl-3,4,6-tri-O-methyl-beta-D-glucopyranose ( 13) are selectively transformed with deacetalisation into the correspo nding acylated glycosyl fluorides 2, 4, 6a g, 8, and 14 by HF/nitromet hane/carboxylic acid anhydride. The reaction is realized without chang e of the ring size if the three-component agent system is mixed some t ime before the carboshydrate is added. 3,5,6-Tri-O-methyl-2-O-pivaloyl -D-glucofuranosyl fluoride (8) and -acetoxyethyl)-3,4,6-tri-O-methyl-a lpha-D-glucosyl fluoride (14) are used as starting materials to synthe size three isomeric, chiral crown ethers, the bis-beta-D-glucofuranosi do-12-crown-4 derivative 12 and both stereoisomeric bis-D-glucopyranos ido-12-crown-4 derivatives 20 and 21.