A Novel C–N Migration Rearrangement Based on N–F Compounds for the Synthesis of N‐Alkyl Diaryl Ureas

A novel rearrangement reaction based on the structure of N‐fluoro‐N‐(phenylsulfonyl) benzamides (FPSBA) was developed. In the presence of base, unsymmetrical N‐alkyl diaryl ureas were obtained in good yields which were accomplished through secondary alkyl phenylamines initiated 1,2‐phenyl‐shift migration rearrangement of N‐fluoro‐N‐(phenylsulfonyl) benzamides. The reaction was carried out without using traditional, highly toxic reagents and noble metals. Whereas without rearrangement occurrence for primary phenylamines and aliphatic amines, normal amides and N‐(phenylsulfonyl) benzamides were afforded respectively. Nitrene and phenyl isocyanate included process were prevented and a secondary alkyl phenylamine initiated vicinal SN2' reaction occurred. This rearrangement reaction features an interesting reaction mechanism, mild reaction conditions, simple operation, and useful products. A novel aryl C–N shift rearrangement reaction to form alkyl diaryl ureas from facilely available FPSBA derivatives was developed. FPSBA selectively reacted with secondary alkyl phenylamines to afford unsymmetrical alkyl diaryl ureas in good yields through a vicinal SN2' mechanism rather than the traditional isocyanate intermediate pathway.