title: Efficient cross-coupling of aryl Grignard reagents with alkyl halides by recyclable ionic iron(III) complexes bearing a bis(phenol)-functionalized benzimidazolium cation.
abstract: A novel bis(phenol)-functionalized benzimidazolium salt, 1,3-bis(3,5-di-tert-butyl-2-hydroxybenzyl)benzimidazolium chloride (H3LCl, 1), was designed and used to prepare ionic iron(III) complexes of the type [H3L][FeX4] (X = Cl, 2; X = Br, 3). Both 2 and 3 were characterized by elemental analysis, Raman spectroscopy, electrospray ionization mass spectrometry and X-ray crystallography. The catalytic performances of 2 and 3 in cross-coupling reactions using aryl Grignard reagents with primary and secondary alkyl halides bearing β-hydrogens were studied. This analysis shows that complex 2 has good potential for alkyl chloride-mediated coupling. In comparison, complex 3 showed slightly lower catalytic activity. After decanting the product contained in the ethereal layer, complex 2 could be recycled at least eight times without significant loss of catalytic activity.
authors.affiliation: The Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China. sunhm@suda.edu.cn.
authors.forename: Chong-Liang
authors.initials: CL
authors.lastname: Xia
authors.forename: Cun-Fei
authors.initials: CF
authors.lastname: Xie
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Wu
authors.forename: Hong-Mei
authors.initials: HM
authors.lastname: Sun
authors.forename: Qi
authors.initials: Q
authors.lastname: Shen
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang