Organofluorverbindungen und Fluorierungsagenzien, 9. Von Glycosylfluoriden zu chiralen Kronenethern

Abstract

Methyl D-galactofuranoside (l), methyl D-glucofuranoside (3), 3-0-substituted 1,2 : 5,6-di-O-isopropylidene-c~-~-glucofuranoses (5a-g), 1,2-O-isopropylidene-3,5,6-tri-O-methyl-c~-~-glucofuranose (7) as well as the trans-decalin analog 1,2-O-ethanediyl-3,4,6-tri-O-methyl-~-~-glucopyranose (13) are selectively transformed with deacetalisation into the corresponding acylated glycosyl fluorides 2, 4, 6a-g, 8, and 14 by HF/nitromethane/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-~-glucofuranosyl fluoride (8)and 2-O-(2-acetoxyethyl)-3,4,6-tri-O-methyl-c~-~-glucosyl fluoride (14) are used as starting materials to synthesize three isomeric, chiral crown ethers, the bis-~-~-glucofuranosido-12crown-4 derivative 12 and both stereoisomeric bis-D-glucopyranosido-12-crown-4 derivatives 20 and 21.

Strategien zur Erforschung neuer Reaktionen

“…Zur Herstellung von Glycosylfluoriden [105] ist eine Vielzahl von Fluorierungsreagentien entwickelt worden, z. B. HF, [106] 2-Fluor-1-methylpyridiniumtosylat, [107] Diethylaminoschwefeltrifluorid (DAST), [108][109][110] HF/Pyridin, [111][112][113] CF 3 ZnBr/TiF 4 , [114] DEAD/PPh 3 /Et 3 O·BF 4 , [115] Selectfluor, [116] Deoxofluor, [117] N,N-Diisopropyl(1-fluor-2-methyl-1-propenyl)amin, [118] HF/MeCN/Ac 2 O, [119] AgF, [120] ZnF 2 , [121] Et 3 N-HF, [122] CF 3 ZnBr, [114] DAST/N-Bromsuccinimid(NBS)/N-Iodsuccinimid(NIS) [123,124] 4-Methyl(difluoriod)benzol, [125] TBAF [126] und PhI(OAc) 2 /SiF 4 . [127] Am häufigsten angewendet werden DAST, HF/Pyridin und DAST/NBS.…”

Modified natural substances—fluorinated and fluoroalkylated monosaccharides and inositols

“…We could show that a mixture from hydrogen fluoride, acetic acid anhydride and nitromethane allows the simultaneous realization of three reaction steps, i.e. acetal cleavage, acetylation and fluorination as a one pot reaction [24][25][26][27][28]. Examples of such Tandem-reactions are shown in Scheme 3.…”

“…The compounds 3, 5, 7 and 8 were directly transformed into the glycosyl fluorides 4, 6, and 9, respectively [24][25][26][27][28]. Undesired ring expansion of furanoses or contraction of pyranoses are completely suppressed.…”

Sugar Derived Crown Ethers and Their Analogs: Synthesis and Properties

“…Different method for the preparation of sugar crown ethers also connecting the C-1 and C-2 positions was elaborated by Mietchien [57,58] (Scheme 16 and 17). The final step -closure of the macrocyclic ring -was based on the intramolecular glycosylation in the presence of appropriate cations as templates.…”