Figure shows the energy diagram for the carbon-migration step of 1a-TFA at the DLPNO-CCSD/def2-TZVPP(D)//CAM-B3LYP-D3(BJ)/6-31(+)G(d,p) level of theory (for details, see Supporting Information, Section 4.4). The thermal stability of the precursor for the meta-insertion product, pro-2,3, exceeded that of the para-insertion precursor, pro-3,4. Despite the higher stability of pro-2,3, the experimental observation of selectively obtaining the para-insertion product implies that the selectivity for the insertion position is under kinetic control rather than thermodynamic control. The oxidation of pro-2,3 and pro-3,4 is expected to occur at a lower energy level than that of the initial material, a pyrrole derivative, owing to the unstable nature of the radical cation intermediate. This instability leads to rearomatization, forming pyridine and promoting the second oxidation step. The rapid progression of the second oxidation step indicates kinetic control of the reaction. Further analysis revealed that a ΔG ‡ of 18.67 kcal mol -1 is necessary for the ring-opening of the cyclopropane formed at the 2,3-position to complete a meta-insertion (II-TS-pro2,3). In contrast, the formation of II from IV via a distonic radical cation (Figure ), which leads to the para-insertion intermediate, Based on the experimental result that the para-insertion product was selectively obtained and from the theoretical calculation, it is suggested the selectivity for the insertion position is kinetic control rather than thermodynamic control.