Synthesis of Rare Carbohydrates and Analogues Starting from Enantiomerically Pure 7-Oxabicyclo(2.2.1)heptyl Derivatives (Naked Sugars)

Recent applications of the naked sugar methodology are reviewed. General methods have been developed to transform enantiomerically pure 7-oxabicyclo­(2.2.1)heptyl derivatives into rare monosaccharides, carbasugars, into a new doubly-branched imino-dideoxyalditol (iminosugar), into long-chain carbohydrates, C-disaccharides, imino-C-disaccharides and new polyhydroxylated quinolizidines. The methods allow to prepare both enantiomers of a given target with the same ease. Predictable high stereoselectivity of the reactions of the bicyclic chirons adds to the flexibility of the approach that can lead to a large molecular diversity.