Catalytic electron donor–acceptor complex triggered cascade radical trifluoromethylation/cyclization of <i>N</i> -isopentenyl aldehyde hydrazones

-isopentenyl aldehyde hydrazones triggered by a catalytic electron donor-acceptor (EDA) complex was developed for the construction of C5-trifluoromethylated tetrahydropyridazines. A catalytic amount of tris(4-bromophenyl)amine was used as the electron donor with trifluoromethyl thianthrenium triflate as the acceptor to generate a trifluoromethyl radical after irradiation. This environmentally benign methodology eliminates the need for a photocatalyst, offering a straightforward and efficient approach to accessing C5-trifluoromethylated tetrahydropyridazines.