Eosin Y as a direct hydrogen-atom transfer photocatalyst for the C3-H acylation of quinoxalin-2(1H)-ones

Visible light promoted eosin Y catalyzed selective C3-H acylation of quinoxalin-2(1H)-ones has been developed in a green and sustainable manner. In contrast to the conventional anionic eosin Y-based photoredox process, neutral eosin Y acts as the actual catalyst, which was responsible for the hydrogen-atom transfer (HAT) process to generate the acyl radical with readily available aldehydes as the radical precursor.