Heterogeneous Catalysts for the One-Pot Synthesis of Chemicals and Fine Chemicals

The success of a given multistep sequential or multicomponent process requires a balance of equilibria and a suitable sequence of reversible and irreversible steps. The simplest way to perform a multistep synthesis is to perform the consecutive steps not only in the same vessel but also under the same reaction conditions. Substituted phthalides are an important class of natural compounds with a variety of important biological properties, whose heterocyclic motif appears in many bioactive compounds. The synthesis is based in two consecutive steps which involves first the condensation of the phthalaldehydic acid with the ketone following the regular mechanism of an acidcatalyzed aldol condensation, giving an aldol intermediate which subsequently lactonize to the target compound. The heptanal self-condensation can be avoided, to some extent, by maintaining a very low concentration of heptanal with respect to benzaldehyde in the reaction mixture.