Organocatalytic Asymmetric Mannich Reaction of Aromatic Imines

Various multifunctional enantiomerically pure organocatalysts were synthesized and screened in asymmetric Mannich reaction. Aromatic imines gave Mannich adducts with malonates in the presence of amino acid derived catalyst in very high enantiomeric purities (ee up to 98%). It is proposed that the network of hydrogen and halogen bonds with Lewis bases, together with the steric effect of the tert -butyl group of the catalyst, is responsible for the high stereoselectivity of the reaction.