Catalysis by Organic Solids. Stereoselective Diels−Alder Reactions Promoted by Microporous Molecular Crystals Having an Extensive Hydrogen-Bonded Network

Abstract

Anthracenebisresorcinol derivative 1 as an organic network material shows a novel catalysis in the solid state for the acrolein−cyclohexadiene Diels−Alder reaction. The suggested mechanism involves a catalytic cycle composed of sorption of the reactants in the cavities of polycrystalline host 1, preorganized intracavity reaction, and desorption of the product. The host also promotes stereoselective intracavity reactions for alkyl acrylates and cyclohexadiene but, in this case, not in a catalytic manner. Relevance of the present system as a functional organic analog of zeolites is discussed in light of the kinetics of respective elementary processes and the effects of pulverization of the catalyst thereupon as well as X-ray crystal structures.