Enantioselective catalysis over chiral imidazolidin-4-one immobilized on siliceous and polymer-coated mesocellular foams

A highly efficient and enantioselective organocatalyst, imidazolidin-4-one, has been successfully immobilized on siliceous MCF and polymer-coated MCF. The resulting heterogenized catalyst demonstrated excellent catalytic performance and recyclability for Friedel-Crafts alkylation and Diels-Alder cycloaddition. The performance of the supported catalysts in relation to the surface environment of siliceous MCF was examined. It was found that partially pre-capping the MCF with TMS groups enabled us to attain well-dispersed catalysts on the siliceous support with optimal performance. We have also developed a polymer-coated MCF, which retained the porous structure of MCF without the surface silanol groups. High reactivity and excellent recyclability were achieved by the organocatalyst immobilized on polymer-coated MCF.