The reaction mechanism for N-methylindole and keto ester catalyzed by In X3(X=F, Br) was studied by the density functional theory(DFT). The geometries and the frequencies of reactants, intermediates, transition states, and products have been calculated at the B3LYP/6-31+G(d, p) level, dichloroethane(DCE) is used as a solvent and the Lan L2 DZ basis has been used for In atom. Transition states have been confirmed by the corresponding vibration analysis and intrinsic reaction coordinate(IRC). In addition, nat...