Pseudo-sugars 5 -

Sulfinylacrylate 41 has been successfully used in the enantioselective synthesis of pseudo-sugar [46, 47]. Cycloaddition of (S)-3-(2-pyridylsulfinylacrylate) (41) with furan and 3,4-dibenzyloxyfuran under Et2AlCl catalysis afforded cycloadducts 42, 43 and 44 (Equation 3.12) which were converted into pseudo-manno-pyranoses 45, 46 and 47 (Figure 3.5). 

In another version of this method, the radical generated by radical exchange from the aryl telluride carbohydrate 83 and the N-acetoxy-2-thiopyridone affords, after intramolecular cyclization and desulfanylation, the polyhydroxylated and phosphorylated pseudo sugar 84 [54] (Scheme 23). 

CHEMISTRY OF CARBA-SUGARS (PSEUDO-SUGARS) AND THEIR DERIVATIVES... 

Carba-sugars (pseudo-sugars) and their derivatives, chemistry of, 48, 21 - 90 Carbohydrate chemistry anomeric and exo-anomeric effects in, 47, 45-123... 

T. Suami and S. Ogawa, Chemistry of carba-sugars (pseudo-sugars) and their derivatives, Adv. Carbohydr. Chem. Biochem., 48 (1990) 21-90. 

Stick RV (1997) The Synthesis of Novel Enzyme Inhibitors and Their Use in Defining the Active Sites of Glycan Hydrolases. 187 187-213 Stutz AE, see de Raadt A (1997) 187 157-186 Stumpe R, see Kim JI (1990) 157 129-180 Suami T (1990) Chemistry of Pseudo-sugars. 154 257-283 Suppan P (1992) The Marcus Inverted Region. 153 95-130 Suzuki N (1990) Radiometric Determination of Trace Elements. 157 35-56 Tabakovic I (1997) Anodic Synthesis of Heterocyclic Compounds. 185 87-140 Takahashi Y (1995) Identification of Structural Similarity of Organic Molecules. 174 105-134 Tasi G, Palinkd I (1995) Using Molecular Electrostatic Potentid Maps for Similarity Studies. 174 45-72... 

In the pseudo-sugar family there are 32 theoretically possible stereoisomers, including anomer-like compounds, and up to the present time, all the predicted sixteen racemic pseudo-sugars have been prepared, as well as ten optically active enantiomers. In the present review, preparations of pseudo-sugars, pseudo-p-fructopyranoses and biological effects of pseudo-sugars will be described. 

The first McCasland s pseudo-sugar, pseudo-a-DL-talopyranose (P) was synthesized from 4-acetoxy-2,3-dihydroxy-5-oxo-cyclohexanecarboxylic acid (6) as follows [13]. Reduction of the oxo acid 6 with sodium borohydride and subsequent esterification with methanol and trifluoroacetic acid, followed by acetylation gave methyl (1, 2, 3, 4/5)-2, 3, 4, 5-tetraacetoxycyclohexanecarboxylate (7). Hydrogenation of 7 with lithium aluminium hydride and successive acetylation yielded pseudo-a-DL-talopyranose pentaacetate (8). Hydrolysis of 8 in ethanolic hydrochloric acid gave pseudo-a-DL-talopyranose 9 in 23% overall yield from 6 [1] (Scheme 6). 

For the sake of convenience, the numbering of a pseudo-sugar has been used tentatively in this article in the analogous numbering of a true hexopyranose. 

Four new pseudo-sugars having ce-ido, a-manno, P-altro and P-manno configurations have been synthesized from the Diels-Alder adduct 33 by the following method. Bromolactonization of 33 with hypobromous acid gave 2-e.w-bromo-4,8-dioxatri-cyclo[4.2.1.03,7]nonan-5-one (38). Reduction of 38 with lithium aluminium hydride,... 

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