Glucopyranosyl fluoride

Glycosylations utilizing the aforedescribed glycosyl fluorides are described next. In 1981, Mukaiyama and coworkers attempted to prepare 1,2-cw-glycosides by utilizing the relatively stable (as compared with other glycosyl halides) 2,3,4,6-tetra-0-benzyl-)8-D-glucopyranosyl fluoride (47)5)... 

The Mukaiyama condensation method was also utilized in the synthesis of several antibiotics and related bioactive substances. These syntheses include apramycin, using 4-azido-2,3,6-tri-(P-benzyl-4-deoxy-) -D-glucopyranosyl fluoride (prepared from the corresponding a-D-glucopyranosyl chloride by the AgF method ) avermectin B , using protected sugar derivatives of oleandrosyl fluoride (a-L-Ole-F) and 0-(a-L-01e)-(1 4)-a-L-0le-F (both... 

Noyori and coworkers found that tetrafluorosilane or trimethylsilyl tri-flate catalyzes the condensation of appropriately protected glycopyranosyl fluorides with trimethylsilyl ethers or alcohols. The strong affinity of silicon for fluorine was considered to be the driving force for this reaction. In the case of Sip4, attack of a nucleophile on the glycosyl cation-SiFj ion-pair intermediate was anticipated. Thus, condensation of 2,3,4,6-tetra-O-benzyl-a- and - -D-glucopyranosyl fluorides (47a and 47fi) with methyl... 

Trialkylsilane resin (PS-DES) 50 was incorporated for solid-phase glycosylation by anchoring a glycosyl donor via their corresponding thio-phenyl ether or 3-glucopyranosyl fluorides (Scheme 20) [59]. Disaccharides... 

H. P. Wessel and N. Ruiz, a-Glucosylation reactions with 2,3,4,6-tetra-0-benzyl-/j-D-glucopyranosyl fluoride and triflic anhydride as promoter, J. Carbohydr. Chem., 10 (1991) 901-910. 

W. R. Figures and J. R. Edwards, a-D-Glucopyranosyl fluoride as a D-glucopyr-anosyl donor for a glycosyltransferase complex from Streptococcus mutans FA1, Carbohydr. Res., 48 (1976) 245-253. 

On treatment of tri-O-acetyl-D-glucal with chlorine and silver fluoride,198 all four possible isomers were formed tri-0-acetyl-2-chloro-2-deoxy-a-D-mannopyranosyl fluoride (16%), tri-0-acetyl-2-chloro-2-deoxy-/3-D-mannopyranosyl fluoride (16%), tri-0-acetyl-2-chloro-2-deoxy-a-D-glucopyranosyl fluoride (6%), and tri-O-acetyl-2-chloro-2-deoxy-/3-D-glucopyranosyl fluoride (62%). These product ratios differ significantly from those of the corresponding bromofluorination and iodofluorination reactions of tri-O -ace tyl-D-glucal,43,53 and this behavior has been discussed198 in terms of the differences observed between the addition of bromine (or iodine) and chlorine to tri-O-acetyl-D-glu-cal, and the nature of the chlorination reaction itself. 

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