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, alpha-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.

Automated summary

A metal-free tandem one-pot synthesis of 3,3-disubstituted 3,4-dihydroquinoxalin-2(1H)-ones has been achieved using visible-light photoredox catalysis. The method provides the desired products in high yields for various substrates, demonstrating great potential for practical applications.