From L-Rhamnose to Rare 6-Deoxy-L-Hexoses

Efficient and rapid transformation of cheaply available L-rhamnose into all the isomeric 6-deoxy-L-hexoses via regio- and stereoselective nucleophilic displacements of triflates is reported. The synthesis entails regioselective protections, one-pot double displacements of triflates, and cascade inversions. The methodology allows facile access to all the rare 6-deoxy-L-hexoses as stable thioglycoside building blocks.