Iron-catalyzed oxidative cleavage of C–N bonds of tertiary amines: syntheses of unsymmetrical ureas from isocyanates

Abstract

An iron-catalyzed protocol has been developed for the synthesis of unsymmetrical ureas via a cascade of oxidative C–N bond cleavage of tertiary amines and hydroamination of isocyanates. This strategy employs inexpensive FeCl₃ as the catalyst and aqueous TBHP as a benign oxidant in acetonitrile, enabling tertiary anilines to react with various isocyanates at room temperature. The protocol features a broad substrate scope and excellent functional group tolerance, while being operationally simple and scalable. It thus offers a practical and sustainable alternative for the synthesis of ureas.