reaction of carbonyl compounds is efficiently catalyzed by reconstructed hydrotalcites, obtained by treating the Mg−Al mixed oxide with water, as solid base catalysts in the presence of water. The catalysis of the reconstructed hydrotalcites is attributable to the surface base sites, created during the organization of the layered structure, with uniformly distributed strength. Furthermore, the reconstructed
intermediate, which is generated by addition of a saturated nitrile to the catalyst, and acts as a nucleophile for Michael addition to unsaturated nitriles. This work represents a new application of templatecatalysis for C–C bond formation.
Water-soluble calixarenes as new inverse phase-transfer catalysts. Their application to aldol-type condensation and Michael addition reactions in water
Aldol-type condensation and Michael addition reactions of activated methyl and methylene compounds in aqueous NaOH solution have been developed without the need for any added organic solvents. The water-soluble calix[n]arenes, which contain trimethyl-ammoniomethyl groups on the upper rim, were used as inverse phase-transfer catalysts, resulting in the corresponding products in good to excellent yields. (C) 2001 Elsevier Science Ltd. All rights reserved.
Kost; Terent'ew, Zhurnal Obshchei Khimii, 1952, vol. 22, p. 655,657