An efficient kinetic resolution of racemic Betti base with l-(+)-tartaric acid in acetone was developed based on a novel enantioselective N, O-deketalization, by which the enantiopure R-and S-enantiomers of Betti base were obtained as the corresponding N, O-ketal compound and salt with l-(+)-tartaric acid, respectively, in excellent yields with a practically foolproof operation.