One-pot synthesis of N-sulfonylamidines from N-acylsulfonamides enabled by a metal triflate-mediated nonhydrolytic N-deacylation†

A triflate salt-catalyzed nonhydrolytic method for the deacylation of N-acylsulfonamides and subsequent one-pot condensation of the newly formed sulfonamides with N,N-dimethylformamide dimethyl acetal to provide N-sulfonylamidines is presented. A range of aliphatic and aromatic N-acylsulfonamides bearing various N-acyl groups such as acetyl, propionyl, butyrl, isobutyryl, octanoyl, benzoyl, 2-phenylacetyl, and sterically hindered pivaloyl are readily transformed into the corresponding N-sulfonylamidines in good to excellent yields. A variety of functional groups including halogeno, keto, nitro, cyano, hydroxyl, ether, and carboxylic ester are tolerated intact.