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【答案】应助回帖
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我是小兵(金币+10, 翻译EPI+1): xiexie 2011-05-26 23:08:13
sltmac(金币+10): 谢谢~~ 2011-05-29 19:59:55
4.5. Palladium-Catalyzed Kumada Cross-Coupling Reactions with Alkyl magnesium Reagents 烷基镁存在下的钯催化Kumada交叉偶联反应
In 1975, Murahashi and co-workers were the first to demonstrate the use of Pd in cross-coupling reactions of vinyl halides with CH3MgBr.1975年，Murahashi及其同事最先演示了甲基溴化镁存在下钯在乙烯基卤化物偶联反应中应用。Despite significant advances in Ni-and Fe-catalyzed Kumada cross-couplings, Pd-catalyzed alkyl Kumada cross-couplings are limited. 尽管镍和铁催化的Kumada交叉偶联反应取得了重大的进展，把催化的烷基Kumada交叉偶联反应还是有限的。This could be attributed to the high reactivity of Grignard reagents and the higher propensity of Pd-alkyl species to undergo hydride elimination compared to the corresponding nickel-alkyl species.这可以归结于格氏试剂的高反应性和钯烷基类反应相比镍烷基类反应更高的进行β-氢化消除的倾向。
4.5.1. C(sp2)-C(sp3) Cross-Coupling with Alkylmagnesium Reagents. 烷基镁存在下的C(sp2)-C(sp3)交叉偶联反应
In 1984, Hayashi and co-workers strated a significant effect of ligand bite angle on the reaction outcome for primary and secondary alkyl Grignards and zinc reagents (see section 2.3). 1984年，Hayashi 及其同事阐明了配位咬合角对初级和次级格氏和锌试剂反应结果的重要影响。The use of dppf as ligand gave optimal results for both primary and secondary alkyl Grignards. 使用二茂铁为配体，对初级和次级烷基格氏试剂都得到了优化的结果。Since this initial report, dppf has become a very common ligand in both Pd-catalyzed Kumada and Negishi coupling reactions.从这份最初的报道开始，二茂铁逐渐成为在钯催化的Kumada 和 Negishi偶联反应中都很常用的配体。 |
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