l-Cysteine as a water-soluble cation scavenger in the removal of the 2,4,6-trimethoxybenzyl group from thiols

l-Cysteine was used as a water-soluble cation scavenger in the acid-catalyzed removal of the 2,4,6-trimethoxybenzyl (Tmob) group from thiols. After aqueous extraction, the product thiols were isolated in good yields. For most substrates, trifluoroacetic acid (TFA) is the reagent of choice. However, for the deprotection of acid-sensitive compounds, formic acid with an extended reaction time is appropriate.