Soft-Hard Acid/Base-Controlled, Oxidative, N-Selective Arylation of Sulfonanilides via a Nitrenium Ion.

In iodine(III)-catalyzed, dehydrogenative arylations of sulfonanilides, the functionalization of C-C bonds is preferred over the functionalization of C-N bonds. Herein, an unprecedented N-selective arylation of sulfonanilides using soft-hard acid-base (SHAB) control by a nitrenium ion over a carbenium ion is reported. Treatment of sulfonanilides with iodine(III) led to the formation of nitrenium ions (soft), which preferentially react with biphenyls (soft) over bimesityl (hard) to generate C-N bonds. The iodine(III) was generated in situ by using PhI and mCPBA at room temperature.