A new convergent approach to the polycyclic framework of dynemicin A

The polycyclic framework of dynemicin A and analogs with different planar moieties were synthesized based on a the Diels-Alder reaction of pyrones. The synthetic strategy was characterized by the formation of an intermediate tetrahydrobenzophenanthiridine from the Diels-Alder reaction of pyrones with benzyne followed by the thermal decomposition of the resulting compound and CO2 extrusion. The intermediate product was subjected to successive reactions that led to the formation of methylated anthraquinones that were transformed to dynemicin A.