REVERSAL OF DIASTEREOFACIAL SELECTIVITY IN THE INTRAMOLECULAR MICHAEL ADDITION OF δ-CARBAMOYLOXY-α,β-UNSATURATED ESTERS. SYNTHESIS OF N-BENZOYL-D,L-DAUNOSAMINE

Article abstract of DOI:10.1016/S0040-4039(00)89313-2

Contrary to the precedents, 1,3-anti stereoselection was found in the intramolecular Michael addition of ethyl threo-5-carbamoyloxy-4-trialkylsilyloxy-2-hexenoate to culminate in a synthesis of N-benzoyl-D,L-daunosamine.The antiperiplanar effect due to the group at 4-position was revealed to play a major role in the stereoselection in this type of reactions.N-benzoyl-D,L-3-epidaunosamine was also synthesized by 1,2-syn asymmetric induction.