Cyclopalladation in the Periphery of a NHC Ligand as the Crucial Step in the Synthesis of Highly Active Suzuki-Miyaura Cross-Coupling Catalysts
作者:Agnes Fizia、Maximilian Gaffga、Johannes Lang、Yu Sun、Gereon Niedner-Schatteburg、Werner R. Thiel
DOI:10.1002/chem.201702877
日期:2017.10.17
reactivities of all these compounds were investigated in detail as well as their performance in the catalytic Suzuki–Miyaura cross‐coupling reaction. It turned out that the C,C‐coordinated derivatives exhibit high catalytic activities in the coupling of arylboronic acids with aryl chlorides, which is consistent with the generally accepted mechanistic ideas on substrate activation.
从2,4-二氯嘧啶开始,可通过五步反应序列获得4-(2-二烷基氨基)嘧啶基官能化的间苯二甲酰氯。已经找到了导致这些配体衍生的钯NHC配合物的两种途径:通过与相应的NHC-AgCl配合物进行重金属化,可以获得C,N配位的钯(II)配合物。在吡啶中和在K 2 CO 3存在下用咪唑鎓盐处理二氯化钯生成环金属化的化合物,从而得到C,C配位的化合物。详细研究了所有这些化合物的反应性及其在Suzuki-Miyaura催化交叉偶联反应中的性能。结果表明,C,C配位的衍生物在芳基硼酸与芳基氯的偶联中表现出高催化活性,这与普遍接受的底物活化机理相一致。