LiOH.H₂O as a catalyst for Knoevenagel and Gewald reactions

Commercial available lithium hydroxide monohydrate LiOH.H₂O was found to be a novel ‘dual activation’ catalyst for tandem cross Knoevenagel condensation between malononitrile or ethylcyanoacetate and aromatic aldehydes leading to an efficient and easy synthesis of the corresponding arylidenes at room temperature in a short reaction time. In the case of salicyaldehyde the reaction lead to the formation of 3-substituted coumarins. The high efficacy, cheapness and easy availability of LiOH.H₂O prompted us to investigate its validity as a basic catalyst for Gewald reaction.