Mild, selective deprotection of PMB ethers with triflic acid/1,3-dimethoxybenzene

An efficient method for the cleavage of the p-methoxybenzyl protecting group of several alcohols in the presence of 0.5 equiv of trifluoromethanesulfonic acid and 1,3-dimethoxybenzene in dichloromethane at room temperature is described.

Triflic acid and 1,3-dimethoxybenzene in dichloromethane readily cleaves p-methoxybenzyl (PMB) ethers at room temperature, for example, 13 affords 14 in 98% yield.