Pd-Catalyzed Intramolecular Aerobic Oxidative C–H Amination of 2‑Aryl-3-(arylamino)­quinazolinones: Synthesis of Fluorescent Indazolo­[3,2‑b]­quinazolinones

A palladium-catalyzed intramolecular aerobic oxidative C–H amination of 2-aryl-3-(arylamino)­quinazolinones has been developed, providing a variety of substituted indazolo­[3,2-b]­quinazolinone derivatives in moderate to excellent yields. Preliminary mechanistic studies suggested that a palladacycle dimer could be the key intermediate, which underwent a cascade “rollover” cyclometalation and C–H amination sequence. Furthermore, the potential utility of these products has been demonstrated as a new class of blue fluorophores for fluorescent materials.本研究开发了一种钯催化的2-芳基-3-(芳氨基)喹唑啉酮分子内需氧氧化C–H胺化反应，可得到多种取代的吲唑并[3,2-b]喹唑啉酮衍生物，收率中等至优异。初步机理研究表明，钯环二聚体可能是关键中间体，其经历了级联“翻转”环金属化与C–H胺化的串联过程。此外，该类产物作为一类新型蓝色荧光团在荧光材料领域的应用潜力已得到验证。