Organofluorverbindungen und Fluorierungsagenzien, 9. Von Glycosylfluoriden zu chiralen Kronenethern

Organofluorine Compounds and Fluorinating Agents, 9 [1a] . — From Glycosyl Fluorides to Chiral Crown Ethers Methyl D ‐galactofuranoside ( 1 ), methyl D ‐glucofuranoside ( 3 ), 3‐ O ‐substituted 1,2:5,6‐di‐ O ‐isopropylidene‐α‐ D ‐glucofuranoses ( 5a—g ), 1,2‐ O ‐isopropylidene‐3,5,6‐tri‐ O ‐methyl‐α‐ D ‐glucofuranose ( 7 ) as well as the trans ‐decalin analog 1,2‐ O ‐ethanediyl‐3,4,6‐tri‐ O ‐methyl‐β‐ D ‐glucopyranose ( 13 ) are selectively transformed with deacetalisation into the corresponding acylated glycosyl fluorides 2, 4, 6a—g, 8 , and 14 by HF/nitro‐methane/carboxylic acid anhydride. The reaction is realized without change of the ring size if the three‐component agent system is mixed some time before the carbohydrate is added. 3,5,6‐Tri‐ O ‐methyl‐2‐ O ‐pivaloyl‐D‐glucofuranosyl fluoride ( 8 ) and 2‐ O ‐(2‐acetoxyethyl)‐3,4,6‐tri‐ O ‐methyl‐α‐ D ‐glucosyl fluoride ( 14 ) are used as starting materials to synthesize three isomeric, chiral crown ethers, the bis‐β‐D‐glucofuranosido‐12‐crown‐4 derivative 12 and both stereoisomeric bis‐ D ‐glucopyranosido‐12‐crown‐4 derivatives 20 and 21 .