Cyclometallation of arylimines and nitrogen-containing heterocycles via room-temperature C–H bond activation with arene ruthenium(II) acetate complexes
The reaction of [RuCl2(p-cymene)]2 with arylimines and 4 equiv. of KOAc in methanol at room temperature produces stable (N^C)-cyclometallated ruthenium(II) complexes via C–H bond activation/deprotonation. This method can be applied also to nitrogen-containing molecules: N-phenylpyrazole, 2-phenyl-2-oxazoline and benzo[h]quinoline. N-Phenyl-pyrazole, [RuCl2(p-cymene)]2 and diphenylacetylene directly lead to alkyne insertion into the metallacycle C–Ru bond.