Desulfurdioxidative N‐N Coupling of N‐Arylhydroxylamines and N‐Sulfinylanilines: Reaction Development and Mechanism

A highly efficient and chemoselective approach for the divergent assembling of unsymmetrical hydrazines through an unprecedented intermolecular desulfurdioxidative N−N coupling is developed. This metal free protocol employs readily accessible N ‐arylhydroxylamines and N ‐sulfinylanilines to provide highly valuable hydrazine products with good reaction yields and excellent functional group tolerance under simple conditions. Computational studies suggest that the in situ generated O ‐sulfenylated arylhydroxylamine intermediate undergoes a retro‐[2π+2σ] cycloaddition via a stepwise diradical mechanism to form the N−N bond and release SO 2 .