Negishi cross-coupling reactions catalyzed by an aminophosphine-based nickel system: a reliable and general applicable reaction protocol for the high-yielding synthesis of biaryls.
Negishi cross-coupling reactions catalyzed by an aminophosphine-based nickel system: a reliable and general applicable reaction protocol for the high-yielding synthesis of biaryls.
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DOI：
10.1002/chem.201101037
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发表时间：
2011-10
期刊：
影响因子：
--
通讯作者：
R. Gerber;C. Frech
中科院分区：
文献类型：
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作者：
R. Gerber;C. Frech
在空气中，在25 °C下，用溶解在THF中的1，1“，1”-（膦三基）三哌啶（约2.05当量）处理NiCl（2）的NMP溶液形成高活性催化体系，用于多种电子活化的、未活化的、失活的和邻位取代的、杂环的和官能化的芳基溴化物和芳基氯化物与二芳基锌试剂的交叉偶联。在60 °C下在仅0.1摩尔%催化剂（基于镍）存在下在2小时内获得非常高水平的转化率和产率，因此催化剂负载量远低于通常报道的镍催化形式的根岸反应。各种芳基卤化物-其可含有三氟甲基、氟化物或其它官能团，如缩醛、酮、醚、酯、内酯、酰胺、亚胺、苯胺、烯烃、吡啶、喹啉和嘧啶-被成功地转化为相应的联芳基化合物。电子和空间的变化是容忍的两个反应伙伴。实验观察表明，分子（Ni（I）/Ni（III））机制是有效的。
Treatment of NMP solutions of NiCl(2) with 1,1',1''-(phosphanetriyl)tripiperidine (≈2.05 equiv), dissolved in THF, in air at 25 °C forms a highly active catalytic system for the cross-coupling of a large variety of electronically activated, non-activated, deactivated, and ortho-substituted, heterocyclic, and functionalized aryl bromides and aryl chlorides with diarylzinc reagents. Very high levels of conversion and yields were obtained within 2 h at 60 °C in the presence of only 0.1 mol% of catalyst (based on nickel) and thus at catalyst loadings far lower than typically reported for nickel-catalyzed versions of the Negishi reaction. Various aryl halides-which may contain trifluoromethyl groups, fluorides, or other functional groups such as acetals, ketones, ethers, esters, lactones, amides, imines, anilines, alkenes, pyridines, quinolines, and pyrimidines-were successfully converted into the corresponding biaryls. Electronic and steric variations are tolerated in both reaction partners. Experimental observations indicate that a molecular (Ni(I)/Ni(III)) mechanism is operative.