The Knoevenagel condensation is an important C-C bond forming reaction which has been extensively studied and also applied in industrial processes. Although it involves a dehydration step, the reaction can be successfully carried out in water to produce electron deficient alkenes and heterocyclic compounds such as coumarins.
Here we review our works and recent articles concerning the Knoevengel condensation in water. The review is split up in two sections: the first dealing with Knoevenagel condensations in water under heterogeneous catalysis, and the second showing examples of uncatalysed Knoevenagel condensations in water.
Keywords: Aqueous medium, Coumarins, Electron deficient olefins, Electron poor alkenes, Heterogeneous catalysis, Knoevenagel condensation, Uncatalysed reaction, Water, environmental legislation, enviro-economic factors, Green Chemistry, chlorinated hydrocarbon