Diastereoselective C-C bond formation at C-5 of vinyl sulfone-modified hex-5-enofuranosyl carbohydrates: diversity-oriented synthesis of branched-chain sugars and beyond.

This is the first report on the diastereoselective addition of carbon nucleophiles to vinyl sulfone-modified hex-5-enofuranosides. The stereoelectronic properties of the substituents at the C-3 position and their interactions with the incoming carbon nucleophiles control the diastereoselectivity of addition at the C-5 position, favoring the formation of l-ido derivatives as major products in most of the cases studied. This new concept of stereocontrolled carbon-carbon bond formation in vinyl sulfone-modified carbohydrates is general in nature. The novel chirons generated by this diversity-oriented synthetic method have been implemented in the preparation of a wide range of hexofuranosyl C-5 branched-chain sugars, bicyclic derivatives, chirally pure enals, and densely functionalized carbocycles.