Visible-Light-Induced Direct Methylation of Quinoxalin-2(1 <i>H</i> )-ones with <i>N</i> , <i>N</i> , <i>N</i> ′, <i>N</i> ″, <i>N</i> ″-Pentamethyldiethylenetriamine as the Methyl Source

Herein, a facile visible-light-driven methylation of quinoxalin-2(1<i>H</i>)-ones with <i>N</i>,<i>N</i>,<i>N</i>',<i>N</i>″,<i>N</i>″-pentamethyldiethylenetriamine as a methyl source was reported. This protocol features broad compatibility and scalability. The transformation was driven by direct irradiation with visible light, requiring no external photocatalyst. Mechanistic investigations reveal an oxygen-triggered radical pathway, excluding EDA complex or PET processes. A practical route to 3-methylquinoxalin-2(1<i>H</i>)-ones was thus established.