Cross-coupling of alkyl halides with aryl or alkyl Grignards catalyzed by dinuclear Ni(ii) complexes containing functionalized tripodal amine-pyrazolyl ligands
作者:Fei Xue、Jin Zhao、T. S. Andy Hor
DOI:10.1039/c3dt32111h
日期:——
Structurally distinctive dinuclear Ni(II) complexes with furan or thiophene tethered amine-pyrazolyl tripodal hybrid ligands have been synthesized and crystallographically characterized. All complexes are catalytically active towards cross-coupling of aryl/alkyl Grignard reagents with β-H containing alkyl halides at room temperature in the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA). The catalytic efficacy of the complexes is dependent on the tether substituent at the central amine. Two species, Ni(II) TMEDA and Mg(II) TMEDA complexes, have been isolated from the catalytic reaction mixtures under different conditions. Some ligand-stabilized Ni(II) and Mg(II) bimetallic species have also been identified in the ESI-MS spectra.
具有独特结构的二核Ni(II)配合物,其配体为带有呋喃或噻吩连接的氨基-吡唑啉三脚架杂化配体,已成功合成并经晶体学表征。所有这些配合物在室温下,并在N,N,N′,N′-四甲基乙二胺(TMEDA)的存在下,对芳基/烷基格氏试剂与含β-H的烷基卤化物交叉偶联反应具有催化活性。配合物的催化效率取决于中心胺的连接基团。在不同的反应条件下,从催化反应混合物中分离出两种物质:Ni(II) TMEDA和Mg(II) TMEDA配合物。在ESI-MS谱中还鉴定出了一些配体稳定的Ni(II)和Mg(II)双金属物种。