Synthesis of orthogonally protected l-glucose, l-mannose, and l-galactose from d-glucose

An efficient route to orthogonally protected l-glucose, l-mannose, and l-galactose is described. Using the strategy to switch the functional groups at C1 and C5 of d-glucose, l-glucose is obtained via a key intermediate C-glycoside. Preparations of l-mannose and l-galactose derivatives from the orthogonally protected l-glucose were accomplished in good yields using the Lattrell–Dax method.