Urea as an Amine Source to Synthesize Primary Aromatic Amines via Nickel-Mediated C−H Amination

Abstract

A straightforward and efficient method has been developed for the transformation of aromatic C_Ar−H bond into C_Ar−NH₂ via nickel-mediated C−H activation, eliminating the need for additional protection and deprotection steps. This strategy employs 8-aminoquinoline as a directing group and urea as the nitrogen source, a non-toxic, inexpensive, and stable bulk chemical. The reaction exhibits high selectivity, exclusively yielding mono-aminated primary aromatic amines. Furthermore, the protocol is tolerant of a wide range of substrates with various functional groups, producing the corresponding ortho-aminobenzamides in yields ranging from 38 % to 73 %. The preliminary results indicate the C−H bond cleavage is likely the rate-determining step in the reaction.