2- Deoxy-2-fluoro sugars

In 1969, Adamson, Foster, and others - reported the synthesis of 2-deoxy-2-fluoro sugars by addition ofCFjOF (in CFCI3, — 80°) to 3,4,6-tri-O-acetyl-l,5-anhydro-2-deoxy-D-flra/)/>zo-hex-l-enitol (61 3,4,6-tri-O-acetyl-D-glucal). The reagent fluorinates 61 electrophilically - °° at C-2, to afford c/v-addition products trifluoromethyl 3,4,6-tri-C)-acetyl-2-deoxy-2-... 

Another interesting use of the imidazylate gr up in the furanoside series has been described by Tann et al. [89]. Thus, treatment of the C-2 imidazylate ester of the a-D-ribofuranoside tribenzoate derivative with KHF2 and HF, at 160°C, led to the 2-deoxy-2-fluoro sugar in 63% yield, presumably through the intermediacy of the fluorosulfate ester (HPLC). The 2-fluoro compound is a key intermediate in the preparation of 2 -fluoro-2 -deoxy D-arabinofuranosyl pyrimidine nucleosides, which exhibit powerful antiherpetic activity [89] (Scheme 12). 

The 5-deoxy-fluoro-sugar derivatives (15) and (16) have been synthesised from D-glucose for incorporation into potential chemotherapeutic nucleosides. Improvements to Ogawa s method for the synthesis of 2-deoxy- -glycosides, involving addition of arylsulphenyl esters of the desired aglycon to glycals, with... 

Syntheses of 3-deoxy-3-fluoro sugars are described next. A rapid synthesis aimed at 3-deoxy-3-[ F]fluoro-D-glucose ( F-3DFG) was developed. ... 

Several fluoro sugars are incorporated into glycoconjugates, and therefore probably compete with the nonfluorinated sugars. Thus, 6-FGal preferentially inhibits Gal incorporation234,306 6-F-Fuc and 2-F-Fuc, the incorporation of L-fucose234,307 and 2-deoxy-2-(fluoroaceta-... 

Aldolases accept a wide range of aldehydes in place of their natural substrates and permit the synthesis of carbohydrates such as azasugars, deoxy sugars, deoxythio sugars, fluoro-sugars, and C8 or C9 sugars. In the case of D-fructose-1,6-diphosphate aldolase (FDP aldolase, Type A), more than 75 aldehydes have been identified as substrates [143]. 

Dihydroxylation of 19 with OSO4/NMO occurred without discrimination between the alkene faces to afford the fluoro sugars ( )-20 and ( )-21 as a 1 1 mixture of separable cis and trans isomers. Synthesis of the 4,4-difluoro-4-deoxy-13-DL-ribo-pyranside derivatives ( )-23e-f and 4,4-difluoro-4-deoxy-13-DL-lyxo-pyranside derivatives ( )-24e-f were realized via transacetalisation of the difluoro homoallylic alcohols 17e-f followed by RCM and dihydroxylation, respectively. 

One year later, Kitazume et al. also described the synthesis of 6-deoxy-6,6,6-trifluoro-D-mannose and D-allose using intermediate (45,55)-76 (Scheme 5.10). Thus, oxidation of 76 with potassium permanganate in the presence of catalytic 18-crown-6 provided the diol 84 as the only isomer in 42% yield. Protection of diol moiety in 84 as its acetonide followed by DlBAL-H reduction afforded the lactol 85, which was subjected to the t-BuOK promoted isomerization to give the desired fluoro sugar 86 in 35% yield. The precursor 87 of fluoro sugar 89 was obtained by reduction... 

Deoxy-4-fluoro-D-glucopyranosyl thymine and 2-deoxy-2-fluoro-D-arabino-furanosyl derivatives of 5-substituted-cytosine and -uracil have been prepared by standard methods from the corresponding fluoro-sugar the uracil derivatives stopped replication of Herpes simplex virus (HSV-1) in vitro. 5-Deoxy-5-iodo-adenosine derivatives have also been prepared from iodo sugars. ... 

Enzymic synthesis of several hexose derivatives from dihydroxy-propanone and glyoeraldehgde derivatives included a preparation of 6-deoxy-6-fluoro-sugars. All four deoxyfluoro-oc-D-glucopyranosyl phosphates have been synthesized and their acid-catalyzed hydrolysis... 

---