Metal-free photocatalytic trifluoromethylative pyridylation of unactivated alkenes

Abstract

An efficient, transition metal-free trifluoromethylative pyridylation of unactivated alkenes was achieved by visible-light-induced photoredox catalysis employing CF₃SO₂Na and a pyridinium salt in the presence of eosin Y as a photoredox catalyst. The overall process is thought to occur by the selective addition of an electrophilic CF₃ radical to the alkene substrate to provide an alkyl radical intermediate, which subsequently engages in an addition to the pyridinium salt. This three-component photocatalytic strategy circumvents traditional multistep procedures and readily affords synthetically and biologically important trifluoromethyl- and pyridyl-containing frameworks.