Silica-gel-supported aluminium chloride: A stable, efficient, selective, and reusable catalyst for tetrahydropyranylation of alcohols and phenols

A simple, effective, and highly chemoselective method to form 2-tetrahydropyranyl ethers of alcohols and phenols in the presence of silica-gel-supported aluminium chloride as a heterogeneous Lewis acid catalyst is described. The catalyst can be easily recovered and reused without appreciable change in its efficiency.