Calcined and silylated K10 montmorillonites as catalysts of pericyclic reactions of trans-anethole

Cation-exchanged K10 montmorillonites are calcined and silylated in order to eliminate acid sites. The solids obtained promote the Diels-–Alder reaction of cyclopentadiene with trans-anethole and the cyclodimerization of trans-anethole.