Ferrous methanesulfonate as an efficient and recyclable catalyst for the tetrahydropyranylation of alcohols and phenols under solvent-free conditions

Abstract

Ferrous methanesulfonate catalyzed tetrahydropyranylation of alcohols (benzylic, primary, isomerical, tertiary, cyclic, allyl, and furyl) and phenols at room temperature under solvent-free conditions has been developed. The catalytic activity of sixteen metal methanesulfonates was compared under the same conditions, ferrous methanesulfonate proved to be the best. It can be recovered easily and reused for several times without distinct deterioration in catalytic activity. During the competitive protection of the hydroxyl groups between an alcohol and a phenol, tetrahydropyranyl ether formed exclusively with the alcohol. A possible catalytic mechanism was proposed.