SYNTHESIS OF A HYBRID ANALOG OF THE ESPERAMICIN AND DYNEMICIN CORES

An enediyne analog (2, R=H) that is a hybrid of the core structures of esperamicin and dynemicin was prepared. The key step in its synthesis was a Reissert-type reaction that involved intramolecular addition of the anion of a Z-1,3-diyn-2-ene to an N-acyl tetrahydrophenathridiniu m intermediate. It was found that 2 (R=H) readily undergoes epoxide re arrangement to an allylic alcohol (16). Both 2 (R=H) and 16 form the s ame cycloaromatized product 17 when heated in MeOH at 45 degrees C. Co pyright (C) 1996 Elsevier Science Ltd