Fluoro sugars synthesis

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. ... 

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-... 

The 6-fluoro derivatives of Gal and Fuc do not decrease the pools of ribonucleotides, nor do they inhibit protein synthesis.234,304 Interestingly, when present in low concentrations, most fluoro sugars do not give cytotoxic effects.304,313 When the size of the halogen atom is increased (Cl — Br — I derivatives), incorporation of L-fucose is lessened, and, for as-yet-unknown reasons, a concomitant increase in cytotoxicity was noted.304... 

One particular class of fluoro-sugars (i. e. glycosyl fluorides) is eminent for their role as gly-cosyl donors in oligosaccharide synthesis. Few excellent reports for applications of glycosyl fluorides in the synthesis of complex oligosaccharides and natural products have been published [51,52]. 

N-Acetylneuraminic acid aldolase, use in fluorinated sugar synthesis, 158,161/ Acylation-hydrolysis of ylides, 2-fluoro-2-oxoalkanoate synthesis, 96-100 Acyl hypofluorites applications, 58 applications for shorter chain homologues, 60,61/ chemistry, 58—61... 

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... 

A review, in Japanese, on the synthesis of fluoro-sugars, together... 

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... 

The bicyclic azetidinium salts 67 were formed by intramolecular ring closure of 5-mesylates 66, even when competitive aziridinium salt formation could have occurred (Scheme 20). The pyrrolidinium salts 68 were obtained similarly. Compounds 67 and 68, with X=F or OMs, were isolable solids. Synthesis of amino-fluoro-sugar derivatives from Al-tosyl-aziridine derivatives is covered in Chapter 8 and 19. 

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... 

---