N-Perfluoroalkylsulfonylimido derivatives of arenecarboxylic acid amides and their oxidative aza Hofmann rearrangement

Abstract

The analogues of carboxamides in which the sp 2-hybridized oxygen atom is replaced by more electron-withdrawing groups, NSO 2CF 3 and NSO 2C 4F 9, have been synthesized. The resulting N-perfluoroalkylsulfonyl arenecarboxamidines ArC( NSO 2R f)NH 2 (R f = CF 3, C 4F 9) undergo an oxidative Hofmann-type rearrangement to the corresponding carbodiimides ArN C NSO 2R f under the action of (diacyloxyiodo)arenes. Rearrangement of related compounds ArC( NSO 2R)NH 2 (R = CH 3, Ph) containing fluorine-free substituents at the sulfonyl group also occurs in similar conditions. It was found that the reactivity of amidines rises with the increasing electron-withdrawing ability of the substituent R.