ENANTIOSELECTIVE SYNTHESIS OF (-)-CONDURAMINE C-1 AND AMINOBROMOCYCLITOL DERIVATIVES

(1S,2R,6R,7R)-4-Phenyl-3,10-dioxa-5-azatricyclo[5.2.1.0(2,6)]dec-4-en-9-one ((+)-5) obtained in 6 steps from the Diels-Alder adduct of furan to 1-cyanovinyl (1S)-camphanate ((+)-3) was reduced to the corresponding endo-alcohol (-)-6 the treatment of which with HBr/AcOH provided (-)-(3aS,4S,6R,7S,7aR)-4 beta-bromo-3a beta,4,5,6,7,7a beta-hexahydro-2-phenyl-1,3-benzoxazole-6 beta,7 alpha-diyl diacetale ((-)-17). Elimination of HBr with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and acidic hydrolysis furnished (-)-(1R,2S,3R,4R)-4-aminocycrohex-5-ene-1,2,3-triol(= (-)-conduramine C-1; (-)-1).