Copper-catalyzed oxybromination and oxychlorination of primary aromatic amines using LiBr or LiCl and molecular oxygen

Nuclear oxybromination of unprotected aromatic primary amines catalyzed by copper(II) acetate [Cu(OAc)(2)] under mild conditions has been developed, in which bromide ions are used as halogenating agents and dioxygen as a final oxidant. The catalyst shows not only high regioselectivity for para- or ortho-isomers but also a remarkable chemoselectivity for monobromination. Oxychlorination of aniline can also be performed under similar conditions, albeit with lower selectivities, with N-phenylacetamide being the main by-product. This simple catalytic method represents ecologically benign and economically attractive synthetic pathway to expensive low-volume aromatic haloamines.