Visible-Light-Mediated Dual Catalytic Spiro Annulation of 2-Aryl Quinazolin-4(3H)-ones with N-Substituted Maleimides

Visible-light-induced, dehydrogenative spiro annulation of 2-arylquinazolin-4(3H)-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.