A Ti4+-exchanged montmorillonite (Ti4+-mont) and a hydrotalcite (HT) are strong solid Brønsted acid and base, and these two clay catalysts could be used in a single reactor without neutralization of active sites. Because the Ti4+-mont have active acid site in the narrow interlayers, the base sites of large HT particles show no interaction with the acid sites. A variety of acid and base reactions, such as esterification, acetalization, deacetalization, aldol reaction, Michael reaction, and epoxidation, proceeded using both the Ti4+-mont and the HT in a single reactor.

A ruthenium-grafted hydrotalcite (Ru/HT) and hydrotalcite-supported palladium nanoparticles (Pd(nano)/HT) are easily prepared by treating basic layered double hydroxide, hydrotalcite (HT, Mg(6)Al(2)(OH)(16)CO(3)) with aqueous RuCl(3)n H(2)O and K(2)[PdCl(4)] solutions, respectively, using surface impregnation methods. Analysis by means of X-ray diffraction, and energy-dispersive X-ray, electron paramagnetic resonance, and X-ray absorption fine structure spectroscopies proves that a monomeric Ru(IV) species is grafted onto the surface of the HT. Meanwhile, after reduction of a surface-isolated Pd(II) species, highly dispersed Pd nanoclusters with a mean diameter of about 70 A is observed on the Pd(nano)/HT surface by transmission electron microscopy analysis. These hydrotalcite-supported metal catalysts can effectively promote alpha-alkylation reactions of various nitriles with primary alcohols or carbonyl compounds through tandem reactions consisting of metal-catalyzed oxidation and reduction, and an aldol reaction promoted by the base sites of the HT. In these catalytic alpha-alkylations, homogeneous bases are unnecessary and the only by-product is water. Additionally, these catalyst systems are applicable to one-pot syntheses of glutaronitrile derivatives.

From the standpoint of atom efficiency, [1] nucleophilic additions to alkenes or alcohols instead of alkyl halides are attractive salt-free methods (Scheme 1). Simple alkenes are readily accessible and abundant carbon-atom sources, but intermolecular additions of 1,3-dicarbonyl compounds to simple alkenes remain problematic. In traditional acid-or base-catalyzed Michael reactions of 1,3-dicarbonyl com-

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4+ exchanged montmorillonite and a hydrotalcite catalyst system are used in a variety of acid and base reactions, such as esterification, acetalization, deacetalization, aldol reaction, Michael reaction, and epoxidation. The catalyst system is easy to prepare and shows high activity and wide applicability and reusability. -(MOTOKURA, K.; FUJITA, N.; MORI, K.; MIZUGAKI, T.; EBITANI, K.; KANEDA*, K.; J. Am. Chem. Soc. 127 (2005) 27, 9674-9675; Dep. Mater. Eng. Sci., Grad. Sch. Eng., Osaka Univ., Toyonaka, Osaka 560, Japan; Eng.) -S. Adam 47-050