All DFT calculations were performed using Gaussian 16 , within M06-2X level of theory . To fully optimize the geometry of structures and subsequently compute frequencies, the 6-31G(d) basis set was employed. As most of the experimental studies have been conducted in dichloromethane, we utilized this solvent for the calculations using the SMD implicit solvation model . Transition structures were located using the Berny algorithm. To further refine the energies obtained from the SMD/M06-2X/6-31G(d) calculations, we carried out single-point energy calculations using a more accurate def2-TZVP basis set . Tight convergence criterion and ultrafine integral grid were also employed to increase the accuracy of the calculations.