Domino [4 + 2] Annulation Access to Quinone–Indolizine Hybrids: Anticancer <i>N</i>‑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).