Domino [4+2] Annulation Access to Quinone-Indolizine Hybrids: Anticancer N-Fused Polycycles

A highly efficient synthetic route to new quinone-indolizine hybrids was accomplished from quinones and N-substituted pyrrole-2-carboxaldehydes via a domino Michael addition-aldol condensation-aromatization sequence through which the central pyridine ring was constructed in atom-economical and environment-friendly manner. Post modification of the resulting products was also demonstrated, enabling further expansion of this heterocyclic chemical space. Biological evaluation of the quinone-indolizine hybrids revealed potent anticancer effects in human prostate adenocarcinoma cells (PC-3) and oral adenosquamous carcinoma cells (CAL-27).