Copper(I)-Catalyzed Amination of Halogenopyridines with Polyamines

CuI-Catalyzed amination of 2-bromo-, and 2-, 3-, and 4-iodopyridines with tri- and tetraamines aimed at the synthesis of N,N′-diheteroaryl derivatives was studied. A strong dependence of the product yields on the nature of starting compounds and the ligand used was observed. The increase in the number of ethene-1,2-diamine fragments in the polyamine structure led to the increase in the yields of polyheteroarylated compounds, whereas propane-1,3-diamine fragments favored the formation of monopyridinyl derivatives and promoted the heteroarylation of the secondary amino groups. 2-Iodopyridine, as a more reactive compound, readily formed N,N-diarylated products. The best yields of the target N,N′-dipyridin-2-yl derivatives were 76% in the case of the triamine and 68% in the case of the tetraamine. A comparison of CuI- and Pd0-mediated heteroarylation of polyamines was also presented.