Coupling dinitrogen and hydrocarbons through aryl migration

摘要

The activation of abundant molecules such as hydrocarbons and atmospheric nitrogen (N-2) remains a challenge because these molecules are often inert. The formation of carbon-nitrogen bonds from N(2)typically has required reactive organic precursors that are incompatible with the reducing conditions that promote N(2)reactivity(1), which has prevented catalysis. Here we report a diketiminate-supported iron system that sequentially activates benzene and N(2)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-2-derived aniline, and the resulting iron species can re-enter the cyclic pathway. Specifically, we show that an easily prepared diketiminate iron bromide complex(2)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(2)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(2)functionalization. This strategy couples nitrogen atoms from N(2)with abundant hydrocarbons, and maps a route towards future catalytic systems.An iron complex sequentially activates N(2)and C-H bonds in benzene to form aniline, with coupling achieved through partial silylation of a reduced iron-nitrogen complex and phenyl migration.