Next, to establish the formation of Int-1 radical in this transformation, we used tetrafluoroalkyl halide 2b with a pendent alkene as a "radical trap" (Scheme 5A). Notably, under our optimized reaction conditions, the use of this bifunctional reagent led to the formation of cyclic compound 7 in moderate yield with 1:3.5 dr. The major diastereomer was confirmed by X-ray diffraction analysis as cis-7. Based on this results and prior mechanistic studies, 9,12 a proposed mechanism is shown in Scheme 5B. Formation of Fe(I) A can undergo halogen-atom abstraction to form the radical 2 • and Fe(II) B species. Then 2 • can escape the solvent cage to undergo radical addition to N-vinyl compound 1 to form the Int • with the concomitant formation of Fe(II) B. In parallel, slow addition of Grignard reagent can promote selective mono-transmetallation of B to form C. 12e Finally, Int • will then undergo selective and reversible radical addition to mono-aryl Fe(II) C to form Fe(III) D. Finally, reductive elimination from C will yield the desired multicomponent product 4 and Fe(I) species A that can then restart the catalytic cycle. [a] Conditions: 1a (0.2 mmol), 2b (0.4 mmol), 3 (0.8 mmol), FeCl3(10 mol %), dcpe (20 mol %), THF (c 1.0 M), 0 °C, slow addition of 3b in 1h, argon atmosphere. [b] 0.4 mmol of 3 was used. [b] Diastereomeric ratio (dr) was determined by crude 1 H-NMR.