IMPORTANCE OF WATER IN ALDOL CONDENSATION-REACTIONS OF ACETALDEHYDE

The condensation of an aldehyde (formaldehyde or acetaldehyde) with vi nyl alcohol has been studied using quantum-mechanical methods. Reactio n models with and without an additional water molecule have been exami ned in parallel. An analysis of the electronic changes during the reac tion has been performed, using a localized orbital approach. The eff e ct of the solvent has been introduced, making use of a continuous diel ectric model developed in our laboratory. Analysis of the reaction mec hanism shows that a water molecule eases the condensation process, and may be considered as a catalyst.