An efficient and recyclable iron(III)-containing imidazolium salt catalyst for cross-coupling of aryl Grignard reagents with alkyl halides

Abstract

1,3-Bis(2,6-diisopropylphenyl)imidazolium chloride, [DIPrim]Cl, was used to produce a novel iron(III)-containing imidazolium salt [DIPrim][FeCl 4 ], which included a N,N -diarylimidazolium cation (R = 2,6-diisopropylphenyl), [DIPrim] + , and tetrachloroferrate(III) anion, [FeCl 4 ] − . This compound was an effective and easy-to-use catalyst for the cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing β -hydrogens. After simply decanting the cross-coupling product in the ether layer, [DIPrim][FeCl 4 ] could be reused in at least four successive runs without significant loss of catalytic activity.