Synthesis of the α-Mannosidase inhibitors swainsonine [(1S, 2R, 8R, 8aR)-1,2,8-trihydroxyoctahydroindolizine] and 1,4-dideoxy-1,4-imino-d-mannitol from mannose
The preparation of the octahydropyrano[3,2-b]pyridine-6,7,8-triol derivative 22, a highly valuable intermediate in the synthesis of (−)-swainsonine, has been achieved by application of a fifteen-step sequence starting from D-mannose with 20% overall yield.