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

Abstract

Visible light‐induced, dehydrogenative spiro annulation of 2‐aryl quinazolin‐4(3H)‐ones with maleimides has been achieved at ambient condition by merging Rh(III)‐catalysis with photo‐redox catalysis. Various spiro‐cyclized quinazolinone derivatives were synthesised 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 (KIE) study, H/D labelling study, and hydrogen peroxide detection tests has been explored. The present methodology was demonstrated to be effective for scale‐up synthesis, enabling the efficient generation of the spirocyclic product.