A new type of rearrangement in branched-chain carbohydrates: isomerization of 3-C-branched aldoses

A new type of rearrangement is described for 3-C-branched chain aldoses. The studied transformation is based on the Mo(VI)-catalyzed isomerization of carbohydrate carbon skeleton and allows preparation of C-3 isomers of 3-C-branched aldoses in a simple way without formation of side products. This rearrangement at C-3 carbon differs from the previously described epimerization at C-2 of aldoses catalyzed by Mo(VI) ions, known as Bílik reaction. The potential of this new transformation is illustrated on the preparation of new, 3-C-methyl-d-glucose and 3-C-vinyl-d-glucose from 3-C-methyl-d-allose and 3-C-vinyl-d-allose, respectively.

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► A new type of rearrangement is described for 3-C-branched chain aldoses.
► The reaction is based on the Mo(VI)-catalyzed isomerization of carbon skeleton.
► Allows preparation of C-3 isomers of 3-C-branched aldoses in a simple way.
► The method leads to preparation of rare saccharides in a single step.