Rh(II) carbene-promoted activation of the anomeric C-H bond of carbohydrates: a stereospecific entry toward α- and β-ketopyranosides.

In this communication we report a new strategy toward ketopyranosides based on a carbene-mediated activation of the anomeric C-H bond of carbohydrates. By forming a new carbon-carbon bond after a glycosylation step, this approach enables the preparation of both α- and β-ketopyranosides from advanced precursors.