Stable ditriflates of D-glucose in the synthesis of iminosugars and polyhydroxyolated pipecolic acids

A synthesis of the five membered iminosugar DAB and a divergent synthesis of the six membered iminosugar 1-dehydromannojirimycin (DMJ) and the corresponding sugar iminoacid are reported. They involve double nucleophilic displacements of a D-xylose ditriflate by benzyl carbazate and a D-glucose ditriflate by allyl amine, respectively. They are followed by a similar protocol consisting of hydrolysis and oxidation or reduction of the resulting bicyclic glycosides. This allowed DMJ to be obtained from the cheap sugar D-glucose.