Mild, efficient and rapid O-debenzylation of ortho-substituted phenols with trifluoroacetic acid

The mild and efficient deblocking of aryl benzyl ethers with TFA is reported. Cleavage was fastest with ortho-electron-withdrawing groups on the phenolic ring, which we have attributed to a proton chelation effect, furnishing the deprotected phenols in excellent yields. The corresponding para-methoxybenzyl, allyl and iso-propyl ethers were also cleanly removed under these conditions. In addition, the selective aryl benzyl ether debenzylation in the presence of benzyl ester, Cbz carbamate and Boc carbamate functionalities was also observed.