I2-Mediated transition-metal-free aromatic C–H amination for the synthesis of benzimidazol-2-ones and related heterocycles

Abstract

A practical iodine-mediated direct aromatic C–H amination reaction has been established for benzimidazol-2-one synthesis under transition-metal-free conditions. The required 1,3-diarylurea substrates are readily accessible by the addition of N-substituted arylamines to the corresponding isocyanates. This versatile and operationally simple synthetic process is broadly applicable to a wide range of 1,3-diarylureas and provides facile access to benzimidazol-2-ones and related heterocycles. Moreover, the present C–H amination reaction can also be performed directly from disubstituted amines and isocyanates without the purification of the urea intermediates in a scalable fashion.