When CuBF4 and CuPF6 were used as catalyst precursor, both the yield and enantioselectivity of the reaction were increased, indicating that weakly coordinated counterion benefits to the reaction (entries 7 and 8). Encouraged by this, we employed copper precursor with large and non-coordination counterion BArF -(tetrakis[3,5bis(trifluoromethyl)phenyl]borane), resulting in a significant improment in the yield and enantioselectivity of the reaction. These results suggested that the reaction requires an electron-deficient catalytic copper(I) center, which is easier to bind to weakly nucleophilic amides.