<i>N</i>,<i>N</i>′-Bisoxalamides Enhance the Catalytic Activity in Cu-Catalyzed Coupling of (Hetero)Aryl Bromides with Anilines and Secondary Amines

Abstract

N,N'-Bis(furan-2-ylmethyl)oxalamide (BFMO), an inexpensive and conveniently available bidentate ligand, is very effective for promoting Cu-catalyzed N-arylation of anilines and cyclic secondary amines. The method enables coupling of a broad range of (hetero)aryl bromides with various (hetero)aryl amines and cyclic secondary amines at 0.5-5 mol % catalyst loadings at relatively low temperatures. For coupling with more sterically hindered acyclic secondary amines, using N,N'-bis(2,4,6-trimethoxyphenyl)oxalamide (BTMPO) as a ligand gives the better results. Additionally, high selectivity is achieved in CuI/BFMO-catalyzed direct monoarylation of piperazine with (hetero)aryl bromides to afford pharmaceutically important building blocks.