ipso-Substitution with Sodium-N-alkyl-(p-nitrobenzene)sulfonamide. A novel anionic rearrangement

Reaction of N-benzyl-N, N-di-(p-nitrobenzene)sulfonamide ( 3 ) with NaCN/HMPA at 140° affords N-benzyl-p-nitroaniline ( 4 ). The same product is obtained upon heating of the sodium salt of N-benzyl-(p-nitrobenzene)sulfonamide ( 5 ). The transformation 5 → 4 is believed to proceed via an anionic episulfonyl compound 6 .