Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

Various multifunctional enantiomerically pure organocatalysts were synthesized and screened in asymmetric Mannich reaction. The reaction of aromatic imines with malonates in the presence of amino acid-derived catalysts gave Mannich adducts in very high enantiomeric purities (up to 98% ee). It is proposed that a 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.