pH-dependent C-C coupling reactions catalyzed by water-soluble palladacyclic aqua catalysts in water
pH-dependent C-C coupling reactions catalyzed by water-soluble palladacyclic aqua catalysts in water
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DOI：
10.1021/om0503592
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发表时间：
2006-01-16
期刊：
影响因子：
2.8
通讯作者：
Fukuzumi, S
中科院分区：
文献类型：
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作者：
Ogo, S;Takebe, Y;Fukuzumi, S
合成了一系列水溶性钯环配合物[（'Bu-SCS）Pd-II（H_2O）]（+）（[1]（+），'Bu-SCS = C_6H_3 - 2，6-（CH_2S 'Bu）（2）），[（Pr-i-SCS）Pd-II（H2O）]（+）（[2]（+），Pr-i-SCS = C6H3- 2，6-（（CH2SPr）-Pr-i）（2）），[（PCP）Pd-II（H2O）]（+）（[3]（+），PCP = C6H3- 2，6-（（OPPr2）-Pr-i）（2）），和[（PC）Pd-II（H2O）（2）]（+）（[4]（+），为了优化催化剂对水中pH依赖性C-C偶联反应的催化活性，通过将相应的钯环氯配合物与银盐在水中反应，合成了PC = 4-MeC_6 H_3 -2-（（OPPr_2）-Pr_i）。PCP）配体以及从三齿（PCP）到二齿（PC）配体。确认在本反应条件下没有钯黑L的沉淀。在水溶性钯环配合物[1]（+）-[4]（+）中，PC钯环配合物[4]（+）对水中的Suzuki-Miyaura、Mizoroki-Heck和Stille偶联反应具有最高的催化活性。这是有史以来报道的水溶性钯催化剂在水中的偶联反应的最高催化活性之一。钯环水溶液催化剂的催化能力与溶液的pH值和载体配体的结构密切相关。通过X射线衍射分析确定了钯环水和氯配合物的结构。
The series of water-soluble palladacyclic aqua complexes [('Bu-SCS)Pd-II(H2O)](+) ([1](+), 'Bu-SCS = C6H3-2,6-(CH2S'Bu)(2)), [(Pr-i-SCS)Pd-II(H2O)](+) ([2](+), Pr-i-SCS = C6H3-2,6-((CH2SPr)-Pr-i)(2)), [(PCP)Pd-II(H2O)](+) ([3](+), PCP = C6H3-2,6-((OPPr2)-Pr-i)(2)), and [(PC)Pd-II(H2O)(2)](+) ([4](+), PC = 4-MeC6H3-2-((OPPr2)-Pr-i)) have been synthesized from the reaction of the corresponding palladacyclic chloro complexes with silver salts in water to optimize the catalytic activity for pH-dependent C-C coupling reactions in water by changing the supporting ligands from S-supporting (SCS) to P-supporting (PCP) ligands and also from tridentate (PCP) to bidentate (PC) ligands. It was confirmed that there was no precipitation of palladium black L under the present reaction conditions. The PC palladacyclic aqua complex [4](+) exhibits the highest catalytic activity among the water-soluble palladacyclic aqua complexes [1](+)-[4](+) for the pH-dependent Suzuki-Miyaura, Mizoroki-Heck, and Stille coupling reactions in water. This is one of the highest catalytic activities ever reported for coupling reactions with water-soluble palladium catalysts in water. The catalytic ability of the palladacyclic aqua catalysts is drastically dependent on the pH of the solution and the structures of supporting ligands. The structures of palladacyclic aqua and chloro complexes were unequivocally determined by X-ray analysis.