A nickel-catalyzed isocyanide insertion reaction with aromatic amines: direct access to open-chain guanidines

Herein, a nickel-catalyzed isocyanide insertion reaction with aromatic amines under open-air conditions is disclosed. A number of open-chain guanidines are successfully synthesized in moderate to good yields and their structures are confirmed by X-ray diffraction analysis. This reaction features mild reaction conditions, readily available starting materials and easy operation. Halogen atoms including F, Cl, Br and I are all compatible with the reaction. Mechanistic studies reveal that oxygen in the air might act as an oxidant.