Diels-Alder Reaction in the Presence of Zeolite

Rate acceleration and selectivity enhancement of organic reactions such as Diels-Alder or Ene reac­ tions using water [1] as a solvent or clay supported reagents [2 ] have recently attracted much interest. The underlaying reason for their influence on the reaction rates and selectivity, has been ascribed to hydrophobic association of the reactants, as in the case of water, or the presence of water and Lewis acid on the surface of the layered structure of clay [1—3], Principly, there exists also the possibility of topological controlled, catalyses of organic reaction within the framework of zeolites. Zeolites, which are crystalline aluminosilicates of usually well-defined structures, differ from clays in one very important respect — their rigid three-dimensional framework contains a system of channels and cavities that do not allow appreciable swelling to occur [4], In this study we have investigated the cycloaddi­ tion reactions of a series of dienes with oxygen-con­ taining dienophiles in the presence of the Cu(I) ion exchanged Y-zeolite [5].