Rapid and efficient chemoselective and multiple sulfations of phenols using sulfuryl imidazolium salts

Phenolic sulfates protected with a trichloroethyl or trifluoroethyl group were rapidly and efficiently obtained by reacting phenols with sulfuryl imidazolium salts in the presence of DBU. Phenolic hydroxyl groups could be sulfated in good yield in the presence of aliphatic hydroxyl groups and multiple sulfations were also readily achieved.