PROBLEMS IN SELECTIVE CATALYSIS WITH MOLECULAR IMPRINTS IN SILICA - SELECTIVE LACTONES FORMATION FROM HYDROXYESTERS IN MICROPORES

Selective lactone formation from hydroxy esters can be obtained with m icroporous glass catalysts. By a sol-gel polycocondensation of TEOS an d a cyclic phosphonate an imprinted microporous silica catalyst was pr epared. The imprint molecule selected is a transition state analogue f or the lactone formation from hydroxy esters. Although selective gamma - and delta-lactone formation from the respective hydroxy esters was o bserved, control experiments revealed, that the catalytic selectivity of the lactone formation is already obtained by the micropores of the material and not associated to the imprint. The study illustrates the importance of proper control experiments for the evaluation of imprint effects in selectively catalyzed reactions.