Knoevenagel condensation of unsymmetrical malonamic esters and malonates on a solid support

Abstract The solid phase synthesis of unsymmetrical substituted methylene malonamic acids 7 and methylene malonic ester mono acids 8 is reported. Resin-bound malonic acid 3 is obtained by treatment of Wang's resin with Meldrum's acid. The free carboxylic acid can be derivatized to afford either esters or amides, which readily undergo Knoevenagel condensation with aldehydes. Cleavage with TFA affords unsymmetrical β-substituted methylene malonamic acids or malonate mono acids.