Mechanistic considerations and characterization of ammonia-based catalytic active intermediates of the green Knoevenagel reaction of various benzaldehydes

Jack van Schijndel (Corresponding author), Dennis Molendijk, Harmen Spakman, Edward Knaven, Luiz Alberto Canalle, Jan Meuldijk

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In the green Knoevenagel reaction of benzaldehyde and malonic acid, the carbon–carbon formation reaction is catalyzed by a double Schiff base formed by benzaldehyde and ammonia. A mechanism for this green Knoevenagel has been proposed. A closed catalytic cycle explains why various ammonium salts, including ammonium bicarbonate, have been correctly reported as catalysts in Knoevenagel-like reactions. Various catalytically active intermediates from derivatives of benzaldehyde were isolated and characterized. Furthermore, these in situ formed double Schiff bases play another catalytic role in the consecutive decarboxylation reaction to various cinnamic acids.
Original languageEnglish
Pages (from-to)323-331
Number of pages9
JournalGreen Chemistry Letters and Reviews
Issue number3
Publication statusPublished - 3 Jul 2019


  • Green Knoevenagel
  • Sustainable Chemistry
  • organocatalysis
  • double Schiff base
  • decarboxylation

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