Efficient method for tetrahydropyranylation/depyranylation of phenols and alcohols using a solid acid catalyst with Wells–Dawson structure

A simple and efficient procedure to form 2-tetrahydropyranyl acetals of phenols and alcohols is reported. Wells–Dawson heteropolyacid catalyst is used both in bulk form or supported on silica, reaction conditions include room temperature and toluene as solvent. Fast deprotection of THP-acetals can be attained by mere change of the solvent using THF–1% MeOH. In both reactions the supported catalyst is easily recoverable and reusable, and the yields are good to excellent.