A combination of heterogeneous catalysis and photocatalysis for the olefination of quinoxalin-2(1H)-ones with ketones in water: a green and efficient route to (Z)-enaminones

Herein, a novel aqueous reaction for the olefination of quinoxalin-2(1H)-ones with ketones through a combinational strategy is described. This reaction features very mild conditions using a simple and cheap catalyst for the synthesis of (Z)-enaminones with moderate-to-good yields. Such a methodology successfully combines the heterogeneous Mannich reaction with photocatalysis, and provides a green and practical approach for the synthesis of potentially bioactive (Z)-enaminones with a 3,4-dihydroquinoxalin-2(1H)-one skeleton.