Axially Chiral Dicarboxylic Acid Catalyzed Asymmetric Mannich Reaction

Significance

The authors have introduced novel axially chiral dicarboxylic acids for an asymmetric Mannich reaction of N-Boc imines and diazo compounds. After evaluating different substituents at the 3,3′-position of the binaphthyl moiety, catalyst 1 has been found to give high enanatioselectivities. With 5 mol% of catalyst 1, moderate to high yields (53-89%) and excellent enantioselectivities (er = 92:8 to 98:2) have been obtained for different arylaldehyde-derived N-Boc imines and tert-butyl ­diazoacetate. Dimethyl diazomethylphosphonate has also been used as the nucleophile and excellent enantioselectivities (er = 96:4 to 98:2) have been obtained.