Visible‐Light‐Mediated Dual Catalytic Spiro Annulation of 2‐Aryl Quinazolin‐4(3<i>H</i>)‐ones with <i>N</i>‐Substituted Maleimides

Visible‐light‐induced, dehydrogenative spiro annulation of 2‐arylquinazolin‐4(3 H )‐ones with maleimides has been achieved at ambient conditions by merging Rh(III)‐catalysis with photoredox catalysis. Various spirocyclized quinazolinone derivatives are synthesized with a broad substrate scope in up to 92% yields at room temperature. A further mechanistic study involving control experiments, UV spectroscopy, light on‐off experiments, kinetic isotope effect study, H/D labeling study, and hydrogen peroxide detection tests has been explored. The present methodology is demonstrated to be effective for scale‐up synthesis, enabling the efficient generation of the spirocyclic product.