An enantioselective alpha-amination of esters by a Lewis base/copper(I) cooperative catalysis strategy has been developed. The transient chiral Cl-ammonium enolate generated from pentafluorophenyl ester and nucleophilic Lewis base is nicely compatible with the copper intermediate formed from N,N-di-t-butyldiaziridinone and Cu(I) to allow for high levels of stereochemical control. The cooperative catalytic reaction leads to a diverse set of highly enantioenriched hydantoins in good yields with excellent enantioselectivities (90-99% ee).