Mechanistic Insight Enables Practical, Scalable, Room Temperature Chan–Lam N-Arylation of N-Aryl Sulfonamides

Sulfonamides are profoundly important in pharmaceutical design. C–N cross-coupling of sulfonamides is an effective method for fragment coupling and structure–activity relationship (SAR) mining. However, cross-coupling of the important N-arylsulfonamide pharmacophore has been notably unsuccessful. Here, we present a solution to this problem via oxidative Cu-catalysis (Chan–Lam cross-coupling). Mechanistic insight has allowed the discovery and refinement of an effective cationic Cu catalyst to facilitate the practical and scalable Chan–Lam N-arylation of primary and secondary N-arylsulfonamides at room temperature. We also demonstrate utility in the large scale synthesis of a key intermediate to a clinical hepatitis C virus treatment.