Superelectrophilic activation in superacid HF/SbF(5) and synthesis of benzofused sultams.

The synthesis of benzofused sultams and/or fluorinated sulfonamides, starting from N-allylic sulfonamides, was performed in superacid HF/SbF(5), through superelectrophilic activation. A dramatic effect of superacid composition on the selectivity of the reaction was shown and applied to the synthesis of cyclic 4-aminobenzenesulfonamides.