SYNTHESIS OF THE ENEDIYNE ANTIBIOTIC ESPERAMICIN-A(1), AND NOVEL ANALOGS FOR TUMOR TARGETING

Two strategies for the construction of the calicheamicin/esperamicin c ore structure are presented. The first is based upon the 2,3-Wittig ri ng contraction of a 13-membered macrocycle 3 (X = CH2 or NCO(2)Me). Th e aza 2,3-Wittig rearrangement of 3 (X = NCO(2)Me) is of particular in terest, as it can potentially lead to compound 6 in one operation. The objective in the second enediyne synthesis project is to obtain both enantiomers of the esperamicin Al aglycone (esperamicinone) via a high ly concise route using the 3,4-cyclohexylidene derivative 17 of (-)-qu inic acid as a common starting synthon.