D-Ribofuranosyl fluoride

The preparation of glycosyl fluorides is described next. Aiming to have a convenient glycosyl donor convertible into 1,2-CM-furanosides, Mukaiyama and coworkers prepared 2,3,5-tri-O-benzyl-yS-D-ribofuranosyl fluoride (36y3) by treatment of a protected D-ribofuranose (35) with 2-fluoro-1 -meth-ylpyridinium tosylate (FMPTs) the total yield was raised by anomerizing the simultaneously produced a-1-fluoride (36a, 7, p 66, 72.f 24 Hz) to 36 (7, F 63.5 Hz, 72,F very small ) by treatment with BF3-OEt2. 

C-Glycosyl derivatives may be prepared by utilizing glycosyl fluorides. Ishido and coworkers reported that the reaction of 2,3,5-tri-O-benzyl-a-(36a) or - -D-ribofuranosyl fluoride (36fi) with isopropenyl trimethylsilyl ether under BF3 catalysis (0.1 -0.05 mol. equiv. for the fluoride, in ether or acetonitrile) gave a mixture of 4,7-anhydro-5,6,8-tri-C)-benzyl-l,3-dideoxy-D-altro- (139, major) and -D-a//o-2-octulose (140) 139 was stated to isomerized to 140 (should be vice versa) under Lewis acid catalysis. Similar... 

Very few of the glycofuranosyl fluorides studied278 [listed in Section III,2d(i)] showed any coupling between F-l and C-3, as, for example, perbenzoylated /3-D-ribofuranosyl fluoride (1.5 Hz). 

The LAOCN3 and TWOSUM programs have been used in the iterative analysis or spectrum simulation of tri-O-acetyl-jS-D-arabinopyranosyl fluoride,252 tri-O-benzoyl-a- and /3-D-ribofuranosyl fluoride,253 and 3,6-anhydro-5-deoxy-5-fluoro-l,2-0-isopropylidene-a-L-idofuranose254 (85). 

Araki, Y, Kobayashi, N, Ishido, Y, S3fnthetic studies with fluorinated intermediates. 3. Highly stereoselective C-a-D-ribofuranosylation. Reactions of D-ribofuranosyl fluoride derivatives with enol trimethylsilyl ethers and with allyltrimethylsilane, Carbohydr. Res., 171, 125-139, 1987. 

Araki, Y, Mokubo, E, Kobayashi, N, Nagasawa, J, Stmctural elucidation and a novel reductive cleavage of ribofuranosyl ring C-l-O bond of the intramolecular C-arylation product of tri-O-benzyl-(3-D-ribofuranosyl fluoride, Tetrahedron Lett., 30, 1115-1118, 1989. 

C. Pedersen and H. G. Fletcher Jr., The anomeric 2,3,4-tri-O-benzoyl-d-ribopyranosyl fluorides and 2,3,5-tri-O-benzoyl-d-ribofuranosyl fluorides. A novel transformation from the d-ribopyranose to the d-ribofuranose series, ]. Am. Chem. Soc., 82 (1960) 941-945. 

Various 3-ribofuranosyl-indoles, -pyrroles and -pyrazoles have been made by reaction of V-blocked heterocycles with 2,3,5-tri-C -benzyl-3-D-ribofuranosyl fluoride.Lithiation of 2,6-dichloroimida2o[l,2-a]pyridine occurs predominantly at C-5, and reaction with a ribono-y-lactone derivative and anomeric deoxygenation gives the 5-ribofuranosyl system 151 with good P-selectivity. The alternative 3-glycosylation pattern 152 could be obtained by palladium-catalysed coupling of 2,6-dichloro-3-iodoimidazo[l,2-a]pyridine with 2,3-dihydrofuran, followed by hydroxylation. Various pyrazolo[4,3-c]pyridine C-nucleosides such as 153 have been made using an effective tetrazole-to-pyrazole transformation carried out on a C-ribofuranosyltetrazole. A paper on the conformational properties of some purine-like C-nucleosides is mentioned in Chapter 21. 

Both anomers of tri- -benzyl-D-ribofuranosyl fluoride with 2-trimethylsilyloxypropene and boron trifluoride gave a very high yield of the acetone compound and both anomers of the... 

C8H15FO4 194.202 Syrup. Mg +81 (c, 1.68 in CHCI3). 5-Benzyl, 2,3-di-Me 5-0-Benzyl-2,3-di-0-methyl-B-D-ribofuranosyl fluoride [115130-24-0]... 

Acetyl-2,3-di-0-benzoyl-p-D-ribofuranosyl fluoride, R-97 2-0-Acetyl-3,5-di-0-benzoyl-p-D-ribofuranosyl fluoride, R-97 2-0-Acetyl-3,4-di-0-benzyl-a-i>fucopyranosyl chloride, F-96... 

Benzyl-1,2 5,6-di- O -isopropylidene- p-L-idofuranose, 1-69 3-0-Benzyl-l,2 4,5-di-0-isopropylidene-m co-inositol, 1-31 3- 0 -Benzyl-1,2 5,6-di- O -isopropylidene- p-L-talofuranose, 1-7 5 5-0-Benzyl-2,3-di-0-methyl-a-D-ribofuranosyl fluoride, R-97... 

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