Synthesis, Characterization and Application of Some Axially Chiral Binaphthyl Phosphoric Acids in Asymmetric Mannich Reaction

Two novel chiral Br?nsted acids 3b and 3c were prepared without involving the complexity of Suzuki coupling. Catalyst 3c bearing two additional hydroxyl groups at 3 and 3 positions of axially chiral 1,1-binaphthalene-2,2-diol phosphoric acid was applied in a model Mannich reaction to afford -amino ester in high yield (92%) and enantiomeric excess (91%) at low reacting temperature of -40 degrees C. In addition, those -amino ester derivatives with high yields and excellent enatioselectivities were obtained in the presence of catalyst 3c under the above condition.