Visible-light-mediated defluorinative cyclization of α-fluoro-β-enamino esters catalyzed by 4-CzIPN

Using 4-CzIPN as an energy transfer (EnT) photocatalyst and alpha-fluoro-beta-enamino esters as substrates, a mild 6 pi-photocyclization/defluorination of N-aryl enamines was carried out to efficiently construct indoles without an oxidant and a transition metal catalyst under visible light irradiation. Mechanistic studies reveal that the triplet N-aryl enamines produced through energy transfer from the excited 4-CzIPN* are responsible for the formation of indoles.

Automated summary

The study demonstrates a mild and efficient method for the construction of indoles using 4-CzIPN as a photocatalyst and alpha-fluoro-beta-enamino esters as substrates under visible light irradiation. Mechanistic studies reveal that the formation of indoles is attributed to the triplet N-aryl enamines produced through energy transfer.