Fe-Catalyzed Radical Trifluoromethylation and Cyclization of <i>Ortho</i>-Vinyl Enaminones with 1-(Trifluoromethyl)-1,3-benzo-[<i>d</i>][1,2]iodaoxol-3(1<i>H</i>)-one to Construct Functionalized Quinolines

Herein, we present a protocol for the construction of functionalized quinolines, i.e., 3-acyl-4-(2,2,2-trifluoro-ethyl)quinolines (ATFQLs) <b>4</b>, from <i>ortho</i>-vinyl enaminones and 1-(trifluoromethyl)-1,3-benzo-[<i>d</i>][1,2]-iodaoxol-3(1<i>H</i>)-one, which was catalyzed by FeCp₂ and promoted by FeCl₃ (Lewis acid) additives in solvents (i.e., acetonitrile and toluene). This strategy first utilized the FeCp₂-catalyzed functionalization of alkenes with trifluoromethyl radicals. The intermediate formed was captured by the <i>ortho</i>-iodobenzoate substrate, yielding intermediate 3, which then underwent the FeCl₃-catalyzed elimination of <i>ortho</i>-iodobenzoate at a higher temperature to form an α,β-unsaturated intermediate. The subsequent intramolecular Michael reaction of the intermediate yielded the final target compound <b>4</b>. In summary, a series of ATFQLs <b>4</b> were synthesized through the formation of two bonds (C═C and C-C).