Solvent-free and selective tosylation of alcohols and phenols with p-toluenesulfonyl chloride by heteropolyacids as highly efficient catalysts

Tosylation of some alcohols and phenols has been directly carried out with p-toluenesulfonyl chloride using heterodoxy acids (H3PW12O40, H3PMo12O40, AlPW12O40, and AlPMo12O40) as catalysts in the absence of solvent. We found that heteropoly acids AlPW12O40 and AlPMo12O40 were effective catalysts for the tosylation of alcohols and phenols. In the case of aliphatic alcohols, secondary alcohols undergo tosylation chemoselectively in the presence of primary hydroxyl groups. This new method consistently has the advantage of excellent yields and short reaction time.Key words: tosylation, p-TsCl, Keggin-type polyoxometalate, solvent-free reaction.