Coupling Dinitrogen and Hydrocarbons Through Aryl Migration

The activation of abundant molecules such as hydrocarbons and atmospheric nitrogen (N) remains a challenge because these molecules are often inert. The formation of carbon-nitrogen bonds from N typically has required reactive organic precursors that are incompatible with the reducing conditions that promote N reactivity, which has prevented catalysis. Here we report a diketiminate-supported iron system that sequentially activates benzene and N to form aniline derivatives. The key to this coupling reaction is the partial silylation of a reduced iron-dinitrogen complex, followed by migration of a benzene-derived aryl group to the nitrogen. Further reduction releases N-derived aniline, and the resulting iron species can re-enter the cyclic pathway. Specifically, we show that an easily prepared diketiminate iron bromide complex mediates the one-pot conversion of several petroleum-derived arenes into the corresponding silylated aniline derivatives, by using a mixture of sodium powder, crown ether, trimethylsilyl bromide and N as the nitrogen source. Numerous compounds along the cyclic pathway are isolated and crystallographically characterized, and their reactivity supports a mechanism for sequential hydrocarbon activation and N functionalization. This strategy couples nitrogen atoms from N with abundant hydrocarbons, and maps a route towards future catalytic systems.