Synthesis of Novel Chelating Benzimidazole-Based Carbenes and Their Nickel(II) Complexes: Activity in the Kumada Coupling Reaction
Synthesis of Novel Chelating Benzimidazole-Based Carbenes and Their Nickel(II) Complexes: Activity in the Kumada Coupling Reaction
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DOI：
10.1021/om8010596
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发表时间：
2009-03-23
期刊：
影响因子：
2.8
通讯作者：
Bouwman, Elisabeth
中科院分区：
文献类型：
--
作者：
Berding, Joris;Lutz, Martin;Bouwman, Elisabeth
以Ni(OAc)(2)和双苯并咪唑盐类为原料，合成了新型螯合型双齿苯并咪唑型N-杂环卡宾的卤化镍(II)配合物。四个配合物的单晶X-射线结构测定表明，镍中心为顺式构型。该配合物是4-氯苯甲醚和4-溴苯甲醚与苯基氯化镁Kumada偶联反应的活性催化剂。活性最高的催化剂在75min内使4-溴苯甲醚完全转化为4-甲氧基联苯，选择性为82%；不到14h，4-氯苯甲醚完全转化为4-甲氧基联苯，选择性为99%。
Nickel(II) halide complexes of novel chelating bidentate benzimidazole-based N-heterocyclic carbenes have been prepared from Ni(OAc)(2) and bisbenzimidazolium salts. Single-crystal X-ray structure determination on four complexes revealed a cis-geometry on a square-planar nickel center. The complexes are active catalysts for the Kumada coupling of 4-chloroanisole and 4-bromoanisole with phenylmagnesium chloride. The most active catalyst gives a complete conversion of 4-bromoanisole within 75 min with a selectivity to 4-methoxybiphenyl of 82% and a complete conversion of 4-chloroanisole in less than 14 h with a selectivity to 4-methoxybiphenyl of 99%.