Development of catalytic reactions using water as a solvent

In recent years, organic reactions in aqueous media have attracted much att ention, not only because these reactions eliminate the necessity of vigorou s drying of solvents and substrates, but also because unique reactivity and selectivity are often observed in the aqueous reactions. Furthermore, orga nic reactions in water may lead to the development of environmentally frien dly chemical processes. We have now developed various types of catalytic or ganic reactions in aqueous media. Catalytic asymmetric aldol reactions in a queous media have attained by using rare earth metal triflates and a chiral multi-dentate ligand. Lewis acid catalysis has become feasible in water by using combinations of water-compatible Lewis acidic cations and anionic su rfactants. These new catalysts were found to form stable colloidal dispersi ons and catalyze various reactions in water. Moreover, Bronsted acid- and p alladium-catalyzed reactions in water have also been performed with the aid of surfactants.