CpCo() and Cu(OAc) bimetallic catalysis for Buchwald-type C-N cross coupling of aryl chlorides and amines under base, inert gas & solvent-free conditions

A strategy involving bimetallic catalysis with a combination of Cp*Co(CO)I 2 and Cu(OAc) 2 was used for performing Buchwald-type C-N coupling reactions of aryl chlorides with amines. The reactions proceeded at 100 °C to produce excellent yields of many of the desired C-N coupled products, in 4 h, under aerobic reaction conditions. The reactions were shown to run under base-free and solvent-free conditions, enabling this strategy to work efficiently for electron-withdrawing and base-sensitive functionalities. The presented methodology was found to be equally efficient for electron-donating functionalities as well as for primary ( 1° ) and secondary ( 2° ) aromatic and aliphatic amines. Moreover, the products were easily separated through the extractions of the organic aqueous layer, with this process chromatographic separations is not required. A strategy involving bimetallic catalysis which requires a combination of Cp*Co(CO)I 2 and Cu(OAc) 2 was used to perform Buchwald-type C-N coupling reactions of aryl chlorides with amines.