Metal-free strategy for C-N cross-coupling of benzamide with sulfonamide enabled by a Smiles rearrangement

N-Substituted anilines and their derivatives are versatile building blocks for synthesizing pharmaceutical molecules, natural products, and functional materials. Given the significant role of biarylamine motifs in modern chemistry, the development of a mild and easily handleable protocol is highly desirable in contemporary organic synthesis. In this context, we develop a transition-metal-free C-N cross-coupling of carboxamides and sulfonamides, resulting in the synthesis of valuable biarylamines and alkylarylamines. This discovery represents an intermolecularly challenging Smiles rearrangement and introduces a method for synthesizing N-substituted anilines through the activation of carboxamides derived from carboxylic acids, a previously unexplored approach. The protocol showcases a broad substrate scope with various functional groups and scalability, providing access to key building blocks in medicinal chemistry and drug discovery. Furthermore, the developed protocol was successfully applied to 20 late-stage modifications of drugs and natural products containing primary amides derived from the corresponding acids.