Nickel(0)/N-heterocyclic carbene complexes catalysed arylation of aromatic diamines

Nickel complexes of N-heterocyclic carbenes were examined for effecting C–N coupling reactions between aromatic diamines and aryl chlorides of varying electron density. The Ni(0) · 2IPr (IPr = N,N′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) complex associated to t-BuONa allowed N,N′-diarylation at 100 °C in 1,4-dioxane with excellent yields. Selective monoarylation of diamines could be performed in THF at 65 °C.

The Ni(0) · 2IPr (IPr = N,N′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) complex associated to t-BuONa allows either selective N-mono or N,N′-diarylation of aromatic diamines in high yields. A two-step procedure for the synthesis of unsymmetrical N,N′-diaryl aromatic diamines is also described.Figure optionsDownload as PowerPoint slide