Stereoselective synthesis of (−)-8-epi-swainsonine starting with a chiral aziridine

An efficient synthesis of (−)-8-epi-swainsonine, starting from a commercially available 1-(R)-α-methylbenzylaziridine-2-methanol, was developed. The synthetic route utilizes stereocontrolled Sharpless asymmetric dihydroxylation governed by AD-mix-β followed by an aziridine ring opening-cyclization sequence to generate the five membered N-heterocyclic ring system present in the bicyclic target. A subsequent stereoselective allylation and piperidine ring forming cyclization then produced a precursor that was converted into (−)-8-epi-swainsonine.