Ruthenium-catalyzed Direct C-H Amidation of Arenes

Chang et al. have reported the ruthenium-catalyzed direct C-H amidation of arenes. According to their results, various aryl ketones or benzamides react with sulfonyl azides in the presence of dichloro(p-cymene)ruthenium(II) dimer catalyst and silver bis(trifluoromethanesulfonyl)imide as an additive, affording the corresponding ortho-amidated products in high yields. In addition, substrates bearing a heterocyclic directing group such as the 2-pyridyl group can be applied to ortho-amidation by using silver hexafluoroantimonate(V) as an additive. Since the obtained ortho-amidated compounds can be converted to various heterocycles, this synthetic method is useful for the synthesis of biologically active compounds.