The reaction mechanism of benzaldehyde and 2-aminopyridine Cu(I)-catalyzed to form N-(pyridin-2-yl)benzamide were studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Four possible reaction pathways were investigated in this study. The result indicates that the CuI is better suitable catalyst for producing N-(pyridin-2-yl)benzamide through CuI and Cu2O of Cu(I)-catalyzed. By comparison, the reaction Re→IMA1→TSA1→IMA2→TSA2→IMA3→TSA3→IMA4→IM6→TS4→P is the main pathway, the activation energy of which is the lowest. IM6→TS4→P is the rate-limiting step, with the activation energy being 260.12 kJ/mol and the reaction heat being 93.01 kJ/mol. The dominant product predicted theoretically is in agreement with the experiment results.
