Iron‐Catalyzed C−H Alkylation/Ring Opening with Vinylbenzofurans Enabled by Triazoles

We report an unprecedented iron‐catalyzed C−H annulation using readily available 2‐vinylbenzofurans as the reaction pattern. The redox‐neutral strategy, based on cheap, non‐toxic, and earth‐abundant iron catalysts, exploits triazole assistance to promote a cascade C−H alkylation, benzofuran ring‐opening and insertion into a Fe−N bond, to form highly functionalized isoquinolones. Detailed mechanistic studies supported by DFT calculations fully disclosed the manifold of the iron catalysis.