(+)-7-Deoxy-6-epicastanospermine 1, (-)-7,8-dideoxy-6-epicastanospermine 2 and (-)-N-acetylslaframine 4 have been synthesized via the stereoselective intramolecular iodocyclization of trichloroacetimidates generated from cis-olefinic allylic alcohols 7 and 15, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.