Chiral phosphoric acid catalyzed the regio- and enantioselective N—H functionalization of N-alkylaniline with pyrazolones derived ketimines as electrophiles, providing a variety of chiral pyrazolones containing a tetrasubstituted stereocenter bearing a new N,N’-acetal motif in excellent yields and high enantioselectivities. This strategy was featured by low catalyst loading, mild conditions, and high efficiency and selectivity.