Visible-light-driven copper(<scp>ii</scp>) catalysis for 2,3-disubstituted quinazolinone synthesis <i>via</i> Ullmann <i>N</i>-arylation and C–H oxidative amidation

A novel visible-light-driven method for the synthesis of 2,3-disubstituted quinazolinones has been developed, employing copper(II) as a catalyst in a sequential Ullmann <i>N</i>-arylation and C-H oxidative amidation process. This methodology utilizes <i>o</i>-iodo-<i>N</i>-substituted benzamides and benzylamines as substrates, with molecular oxygen sourced from ambient air functioning as the oxidant. The reaction is conducted under mild conditions, utilizing cost-effective copper(II) chloride as the catalytic agent and Eosin Y as a photosensitizer, facilitated by blue LED irradiation. A broad compatibility with various substrates is demonstrated, yielding products in the range of 30% to 84%. Additionally, mechanistic studies elucidate a single-electron transfer pathway that incorporates aryl radical intermediates. This research presents a sustainable and efficient strategy for the synthesis of quinazolinones, with considerable synthetic and mechanistic implications.