In addition, in this series of aromatic nucleophilic substitution reactions, there is another concerted-stepwise change.We also calculated the mechanism of aromatic nucleophilic substitution reaction under the condition of KHMDS as a base. Since only 1.5 equivalents of KHMDS were added during the reaction, the amide group in this process was not directly complexed with the metal ion. At this point, both the Meisenheimer intermediate and the dissociation transition state can be optimized, indicating that this reaction is accomplished via a classical stepwise mechanism. In this regard, we believe that here the nucleophilicity of the nucleophile and the leaving ability of the leaving group affect the mechanism. We proposes the following explanation: Approximately, the energy of the molecule depends on its most unstable part, so the energy of reactant depends on the enolate, the energy of intermediate depends on the benzene ring and the energy of product depends on the amide salt. LDA's Lewis acidity makes the enolate and amide salt more stable. Therefore, compared with KHMDS, the energy of the reactants and products is reduced while maintaining the same energy of the intermediate, which is equivalent to increasing the relative energy of the intermediate. As a result, the apparent activation energy rises and the mechanism change from stepwise to borderline, and a dynamic intermediate is present. The reason why the concerted mechanism is difficult to occur in this system is that the reaction is exothermal strongly, and the potential energy curve of the product is too low to inevitably intersect with the intermediate(Fig. ).