Carbocyclic sugar analogs

This would be a good method for the preparation of carbocyclic sugar analogs, since some sugar analogs have potent biological activities. 

Gaudino, J J, Wilcox, C S, A general approach to carbocyclic sugar analogs — preparation of a carbocyclic analog of beta-D-fmctofuranose, Carbohydr. Res., 206(2), 233-250, 1990. 

Similar to the synthesis of its sugar analog 506, the 2-oxazolyl carbocyclic C-nucleoside 519 was prepared from the carbobicyclic hemiacetal 518 and 2-(methylamino)ethanol (76CJC849) (Scheme 134). 

Racemic 2-azabicyclo[2.2.1]hept-5-ene-3-one has great potential as a synthetic intermediate. The bicyclic lactam is a synthon for carbocyclic sugar amines, carbonucleo-sides, and carbocyclic dinucleotide analogs [239]. Chiral 2-azabicyclo[2.2.1]hept-5-ene-3-one 133 is key intermediate for the synthesis of (—)-carbovir 134, an antiviral agent effective against HIV. Nakano et al. [240] prepared chiral 133 by enantioselective trans-... 

Many other variations of the basic structure 10 have been explored, including an-hydro sugars and carbocyclic analogs, the latter derived from quinic acid 13 [23-26]. In summary, the preparation of these materials (e.g. 14-16) requires more synthetic effort than the fructose-derived ketone 10. Occasionally, e.g. when using 14, catalyst loadings can be reduced to 5% relative to the substrate olefin, and epoxide yields and selectivity remain comparable with those obtained by use of the fructose-derived ketone 10. Alternative ex-chiral pool ketone catalysts were reported by Adam et al. The ketones 17 and 18 are derived from D-mannitol and tartaric acid, respectively [27]. Enantiomeric excesses up to 81% were achieved in the epox-idation of l,2-(E)-disubstituted and trisubstituted olefins. 

Barton, D H R, Augy-Dorey, S, Camara, J, DaUco, P, Delaumeny, J M, Gero, S D, Quiclet-Sire, B, Stutz, P, Synthetic methods for the preparation of basic D-pseudo-sugars and L-pseudo-sugars — synthesis of carbocyclic analogs of A-acetyl-muramyl-L-alanyl-D-isoglutamine (Mdp), Tetrahedron, 46, 215-230, 1990. 

Carba sugars are carbocyclic analogs of monosaccharides in which the ring-oxygen atom has been replaced by a methylene group. They were first synthesized by McCasland and coworkers,12 who called them pseudo-sugars, but they... 

Iii this chapter on the hydrazine derivatives of sugars and related compounds, an attempt has been made to offer more than a review of what has already been achieved by focusing on reactions that have not yet been tried on carbohydrate substrates (examples of these are given in Sections III.3 and IV.4). In summary, a serious effort has been made to point to novel approaches for the synthesis of, and new applications for, the reactions of saccharide hydrazones and their carbocyclic analogs. 

Direct Wittig reaction of Ph PCHCOn,Me with the four unsubstituted D-aldopentoses followed by acetylation provides convenient preparative access to acyclic seven-carbon trans-2.3-unsaturated sugar derivatives. These products served as dienophiles for a detailed comparative study in Diels—Alder cycloaddition with cyclopentadiene. Related syntheses afforded analogous cis-dienophiles. Cycloaddition under uncatalyzed thermal conditions gave mixtures of the four possible stereoisomeric norbornene adducts. The endo, exo ratios, and diastereofacial selectivities of the adducts were determined by NMR spectroscopy and by chemical transformations, supplemented by selected X-ray crystallographic analyses. Different distributions of isomers were encountered when a Lewis acid was used to catalyze the cycloaddition. The reaction can be controlled to provide preparative access to selected isomers and thus constitutes a versatile method for chirality transfer from the precursor sugar to four new asymmetric centers in a carbocyclic framework. 

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