Problems in Selective Catalysis with Molecular Imprints in Silica - Selective Lactones Formation from Hydroxyesters in Micropores -

Selective lactone form ation from hydroxy esters can be obtained with m icroporous glass catalysts. By a sol-gel polycocondensation o f TEO S and a cyclic phosphonate an im printed m icroporous silica catalyst was prepared. The imprint m olecule selected is a transition state analogue for the lactone form ation from hydroxy esters. A lthough selective yand ^-lactone form ation from the respective hydroxy esters was observed, control experim ents revealed, that the catalytic selectivity o f the lactone formation is already obtained by the m icropores of the m aterial and not associated to the imprint. The study illustrates the im portance of proper control experim ents for the evaluation o f imprint effects in selectively catalyzed reactions.