A Stereoselective Synthesis of Lentiginosine

A concise stereoselective synthesis of (−)-lentiginosine, an iminosugar endowed with an interesting proapoptotic activity, has been accomplished using an enantiopure pyrroline <i>N</i>-oxide building block derived from d-tartaric acid. Key steps are a totally diastereoselective nucleophilic addition to the cyclic nitrone followed by a combination of two simultaneous and two tandem reactions occurring under the same conditions in a single laboratory operation. Natural (+)-lentiginosine can be synthesized by the same method but starting from l-tartaric acid