A highly efficient catalytic system for cross-coupling of aryl chlorides and bromides with malononitrile anion by palladium carbene complexesElectronic supplementary information (ESI) available: experimental details. See http://www.rsc.org/suppdata/cc/b3/b302890a/
作者:Chengwei Gao、Xiaochun Tao、Yanlong Qian、Jiling Huang
DOI:10.1039/b302890a
日期:——
Six imidazolium chlorides (1–6) as precursors of 1,3-diaryl substituted N-heterocyclic carbene ligands were synthesized and evaluated in palladium-catalyzed cross-coupling reactions of aryl chlorides and bromides with malononitrile in the presence of NaH. Among them, 1,3-bis(2,4,6-triethylphenyl)imidazolium chloride (5) and 1,3-bis(2,4,6-triisopropylphenyl)imidazolium chloride (6) are novel. The catalytic system combining Pd(0) with imidazolium salts 4, 5 and 6 with bulky aryl groups in pyridine is found to be superior over others and afforded α-arylmalononitriles in high yields when employing a wide variety of substrates.
在钯催化的芳基氯化物和溴化物与丙二腈在 NaH 存在下的交叉偶联反应中,合成并评估了六种作为 1,3-二芳基取代的 N-杂环碳烯配体前体的咪唑氯化物(1-6)。其中,1,3-双(2,4,6-三乙基苯基)氯化咪唑鎓(5)和 1,3-双(2,4,6-三异丙基苯基)氯化咪唑鎓(6)属于新型化合物。研究发现,将钯(0)与咪唑盐 4、5 和 6 以及吡啶中的笨重芳基结合起来的催化体系比其他催化体系更优越,而且在使用多种底物时都能高产率地制备出 α-芳基丙二腈。