Ni(II)-salt catalyzed activation of primary amine-sp3Cα-H and cyclization with 1,2-diketone to tetrasubstituted imidazoles

NiCl2 center dot 6H(2)O and Ni(OAc)(2)center dot 4H(2)O were found as efficient catalysts for C-H activation of benzyl and aliphatic amines for an unprecedented multi C-N bond forming cyclization with 1,2-diketones under refluxing toluene to furnish highly substituted and polycyclic imidazoles.