Metal‐Free Tandem One‐Pot Construction of 3,3‐Disubsituted 3,4‐Dihydroquinoxalin‐2(1H)‐Ones under Visible‐Light Photoredox Catalysis

Abstract Visible‐light photoredox‐catalyzed metal‐free tandem one‐pot synthesis of 3,3‐disubstituted 3,4‐dihydroquinoxalin‐2(1 H )‐ones from easily accessible 1,2‐diaminobenzenes, α‐ketoesters and 4‐alkyl Hantzsch esters has been described. This mild transformation affords the desired products in 47–93% yields for diversely decorated substrates, and can proceed on a gram‐scale. The efficacy of the current catalysis arises from the use of organic 1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene (4CzIPN) as the photocatalyst and CF 3 CO 2 H as the additive. magnified image