Cp*Co(iii) and Cu(OAc)2 bimetallic catalysis for Buchwald-type C–N cross coupling of aryl chlorides and amines under base, inert gas & solvent-free conditions

Abstract

A strategy involving bimetallic catalysis with a combination of Cp*Co(CO)I₂ 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.