Rare Earth Metal Trifluoromethanesulfonates as Water-Tolerant Lewis Acid Catalysts in Organic Synthesis

Abstract

Rare earth metal trifluoromethanesulfonates (lanthanide and scandium triflates) are stable in aqueous media and can act as Lewis acid catalysts in several carbon-carbon bond forming reactions. The reactions proceeded smoothly in the presence of a catalytic amount of the triflate under mild conditions in both aqueous and organic solvents. Moreover, the catalysts could be recovered after the reactions were completed and could be reused. Chiral rare, earth metal triflates have also been developed. Unique reactivities and selectivities, which depend on the specific characteristics of the rare earth elements, were observed in the chiral rare earth triflate-catalyzed reactions. 1. Introduction 2. Aldol Reactions 3. Michael Reactions 4. Allylation Reactions 5. Diels-Alder Reactions 6. Friedel-Crafts Acylations 7. Glycosylation Reactions 8. Asymmetric Catalysis 9. Conclusions