Synthesis of trifluoroalkyl or difluoroalkyl phenanthridine derivatives via cascade reaction using an intramolecular cyano group as a radical acceptor under photoredox catalysis

Abstract

In the presence of Ru(phen)₃Cl₂ or fac-Ir(ppy)₃ under visible-light irradiation, the addition of fluorinated radicals to N-arylacrylamides followed by an intramolecular cyano group insertion cascade cyclization process produced trifluoroalkyl or difluoroalkyl phenanthridine derivatives in moderate to good yields. Three easily available fluoroalkylated reagents CF₃SO₂Cl, BrCF₂CO₂Et and BrCF₂PO(OEt)₂ were used as the sources of fluorinated radicals.