Metal‐Free Oxidative C–H Amidation of N , N′ ‐Diarylureas with PhI(OAc) 2 : Synthesis of Benzimidazol‐2‐one Derivatives

Benzimidazol‐2‐ones have various biological functions and are usually prepared by reactions of substituted benzene‐1,2‐diamines with carbonyl‐containing compounds or intramolecular N ‐arylations using substrates with carbon‐halogen bonds. However, the starting materials of these protocols are often not readily available. Herein, a simple and practical metal‐free oxidative C–H amidation of N , N′ ‐diarylureas has been developed that takes place at room temperature. This protocol uses readily available N , N′ ‐diarylureas as the starting materials and inexpensive PhI(OAc) 2 as the oxidant without the need of a catalyst, ligand, or the exclusion of air. The present method has a wide functional group tolerance and affords a new and practical strategy for the synthesis of N‐heterocycles.