Visible-Light-Mediated Three-Component Annulation Strategy for the Synthesis of 2,3-Disubstituted Quinazolin-4(3 H )-ones

We developed a visible-light-mediated, three-component annulation strategy for synthesizing 2,3-disubstituted quinazolin-4(3H)-ones from easily available starting materials under mild reaction conditions. Phenylthiourea intermediates, generated in situ from phenyl isothiocyanates and substituted anilines, undergo formal [4 + 2] annulation with isatins to afford the corresponding products. This process involves two C-N bond formations in a one-pot, two-step protocol. Crucially, the method requires no photocatalysts, transition metals, or external oxidants.