Ionic iron(III) complex of aryloxo-linked bis(imidazolium) cations: efficient and recyclable catalyst for aryl Grignard cross-coupling of alkyl chlorides

Abstract

A novel phenol-linked bis(imidazolium) salt, H3LCl2 (L = O-4-C(CH3)3-C6H2-2,6-di[CH2{C(NCHCHNAr)}]2, Ar = 2,6-diisopropylphenyl, 1), was designed and used to prepare an ionic iron(III) complex [H2L][FeCl4] (2). Complex 2 was a highly efficient catalyst for aryl Grignard cross-coupling of alkyl chlorides bearing β-hydrogens. Furthermore, complex 2 was reusable and could be reused in at least eight times without significant loss in catalytic activity.