A conjugated addition of benzylamine to methyl (4R,SS)-4,5-(isopropylidenedioxy)-(2E)-hexenoate 8a followed by lactonization under acidic condition proceeds to the formal total syntheses of L-daunosamine 4 and L-acosamine 2. On the other hand, direct conjugated addition of benzylamine to methyl (4S,5S)-4,5-epoxy-(2E)-hexenoate 5 and the subsequent intramolecular nucleophilic attack by the ester carbonyl group on the epoxy ring of the substrates leads to the formal total syntheses of D-acosamine 2 and D-ristosamine 1. (C) 2000 Elsevier Science Ltd. All rights reserved.