PREPARATION, CHARACTERIZATION, AND SYNTHETIC USES OF LANTHANIDE(III) CATALYSTS SUPPORTED ON ION-EXCHANGE RESINS

Lanthanide(III) catalysts supported on ion exchange resins (Ln-resins) were prepared from Dowex, Amberlite, Amberlyst, and other cation exch ange resins. The amount of lanthanides on resin supports was measured through EDTA titration. The results indicated that the lanthanides in aqueous solution exchanged with almost all the cations (H+ or Na+) on the resins to form stable ionic complexes between the lanthanides(III) and the resins. The effects of resin types, resin sizes, and lanthani de salts were investigated with a reaction of indole and hexanal in aq ueous solution and with an aldol reaction of benzaldehyde and silyl en ol ether in organic solvents. The study found that among ion exchange resins tested Amberlyst XN-1010 and Amberlyst 15 complexed with lantha nides(III) were the most effective catalysts. In addition, the selecti ve Ln-resins were utilized to catalyze acetalization of aldehydes, ald ol reaction of formaldehyde or benzaldehyde in aqueous solution, nucle ophilic addition to an imine, allylation of an aldehyde, an aza Diels- Alder (DA) reaction, and a ring-opening reaction of an epoxide. Furthe rmore, glycosylation of alcohol using glucosyl fluoride as a donor was also promoted with the Ln-resin. Thus, this work demonstrated potenti al uses of lanthanide(III) catalysts supported on ion exchange resins in routine organic reactions.