Discovery, Scope, and Limitations of an N-Dealkylation/N-Arylation of Secondary Sulfonamides under Chan-Lam Conditions

We report the discovery, scope, and limitations of a Cu-mediated sulfonamide N-dealkylation/N-arylation reaction. Specific secondary N-alkyl sulfonamides undergo Cu-mediated oxidative dealkylation followed by N-arylation under Chan-Lam conditions. The reaction is relatively general, allowing the synthesis of a range of N-aryl secondary sulfonamides in good yield. Mechanistic investigations determined the sequence of reaction events as well as the efficiency-limiting events. Limitations in the methodology are also presented.