Synthesis of 3‐Alkenylated and Amidated Quinoxalin‐2(1H)‐ones via Oxidative Coupling

ABSTRACT An efficient method for the C3─H functionalization of quinoxalin‐2(1H)‐ones is disclosed. Using FeCl 3 /2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) as a catalytic system, acetophenones undergo hydrogen atom transfer to generate enol radicals, which then add to quinoxalin‐2(1H)‐ones followed by tautomerization to afford 3‐alkenylated quinoxalin‐2(1H)‐ones. Given the potential bioactivity of 3‐functionalized quinoxalin‐2(1H)‐ones, we further develop a DDQ‐mediated oxidative coupling between quinoxalin‐2(1H)‐ones and benzamides, providing a series of 3‐amidated derivatives. These oxidative coupling reactions exhibit high atom economy, broad substrate scope, and moderate to excellent yields.