ALPO4-CATALYZED DIELS-ALDER REACTION OF CYCLOPENTADIENE WITH (-)-MENTHYL ACRYLATE - INFLUENCE OF CATALYST SURFACE-PROPERTIES

Different synthetic AlPO4 systems are effective yet mild acid catalyst s for the heterogeneous cycloaddition reaction of cyclepentadiene with (-)-menthyl acrylate. The reaction proceeds selectively under mild co nditions and in a relatively short reaction time with an almost total conversion, a high endo/exo ratio, and a reasonable asymmetric inducti on. When the reactions are carried out without solvent, some correlati ons are obtained between the number of acid sites, titrated with pyrid ine, and reaction yields, endo/exo and diastereofacial selectivities. The positive influence of surface area of catalysts is also determined . However, the lack of good correlations between reaction results and surface properties of the catalysts indicates the influence of some ot her factors.