Functionalized quinolones and isoquinolones <i>via</i> 1,2-difunctionalization of arynes: synthesis of antagonist agent AS2717638 and floxacin key intermediates

Quinolones and isoquinolones are privileged scaffolds in synthetic/medicinal chemistry and drug discovery due to their unique chemical structures and intrinsic properties. Herein, we reveal a transition-metal-free approach for their synthesis from the reaction of dimethyl-2-((phenylamino)methylene)malonate with aryne precursors under mild conditions. The substrate scope is broad, accommodating a wide range of functional groups. The synthetic utility of the developed protocol has been demonstrated in the total synthesis of the potent antagonist agent AS2717638 and key intermediates of floxacin congeners. The gram-scale experiments illustrate its synthetic potential.