Synthesis of anionic iron(II) complex bearing an n-heterocyclic carbene ligand and its catalysis for aryl grignard cross-coupling of alkyl halides

摘要

The reaction of 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) with one equivalent of a novel imidazolium salt of iron(II), [FeBr _3(C_4H_8O)](HIPr)·C_4H _8O (1), afforded the anionic iron(II) complex bearing an N-heterocyclic carbene ligand [Fe(IPr)Br_3](HIPr)·C _7H_8 (2), which shows extremely high activity in comparison with the other iron(II)-based precatalysts in the cross-coupling reaction of 4-tolylmagnesium bromide with cyclohexyl bromide.