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

Visible‐light photoredox‐catalyzed metal‐free tandem one‐pot synthesis of 3,3‐disubstituted 3,4‐dihydroquinoxalin‐2(1H)‐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 CF3CO2H as the additive. [ABSTRACT FROM AUTHOR]