Tungstosilicate salts as catalysts in phenol tetrahydropyranylation and depyranylation

Both reactions were carried out at room temperature, using toluene in the tetrahydropyranylation and methanol in the depyranylation as solvents. It was observed that there is an influence of the acid strength of the different catalysts on the yields obtained in both reactions, although the textural properties of the salts must also be taken into account. The cesium salts were more active than rubidium salts, the latter being only active in the depyranylation reaction.