Nucleophilic Substitution of Tertiary Sulfonamides: Construction of Sulfonate Esters.

Under the combined action of trichloroisocyanuric acid (TCCA) and triflic acid (TfOH), tertiary sulfonamides are efficiently activated, leading to the in situ generation of electrophilic sulfonamide salts. These electrophilic salts subsequently undergo nucleophilic substitution by alcohols, resulting in the formation of sulfonate esters under mild conditions. Other advantages of this method include the absence of transition-metal catalysts, broad substrate applicability, and high functional-group tolerance.