Asymmetric routes to azasugars from chiral bicyclic lactams. Synthesis of 1,4-dideoxy-1,4-imino-D-lyxitol; L-deoxymannojirimycin; rhammo-1-deoxynojirimycin and 1-deoxy-6-epicastanospermine

By employing the appropriate chiral bicyclic lactams, the asymmetric total synthesis of four enantiopure azasugars mentioned in the title were successfully achieved. A series of diastereoselective oxidations (OsO4/NMO) followed by diastereoselective reductions (BH3, 9-BBN) gave good yields of the trisubstituted (16) and tetrasubstituted (2,3,4) pyrrolidine and piperidines respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.