2,4-dimethyl-(1,1’,2’,1”)terphenyl

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: 2,4-dimethyl-(1,1’,2’,1”)terphenyl
• 英文别名: 2,4-Dimethyl-1-(2-phenylphenyl)benzene
• 化学式: C₂₀H₁₈
• 分子量: 258.363
• InChiKey: IYKHQLFOBATXHD-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  5.9
• 重原子数：
  20
• 可旋转键数：
  2
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.1
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为产物：
  描述：

  2,4-二甲基溴苯 、 2-联苯硼酸 在 Pd(CN(2,6-(2,6-(i-Pr)2C6H3)2C6H3))2 、 sodium t-butanolate 作用下， 以 异丙醇 为溶剂， 反应 8.0h， 以76%的产率得到2,4-dimethyl-(1,1’,2’,1”)terphenyl
  参考文献：
  名称：

  Synthetic and Mechanistic Interrogation of Pd/Isocyanide-Catalyzed Cross-Coupling: π-Acidic Ligands Enable Self-Aggregating Monoligated Pd(0) Intermediates

  摘要：

  Despite the large number of judiciously designed ligands that have been exploited in palladium-catalyzed cross-coupling protocols, the incorporation of ligands bearing appreciable pi-acidic properties has remained significantly underexplored. Herein, we demonstrate that well-defined and low-coordinate Pd-0 complexes supported by m-terphenyl isocyanides function as competent catalysts for the Suzuki Miyaura cross-coupling of aryl bromides and arylboronic acids. Two-coordinate Pd(CNArDiPP2)(2) was active for the coupling of unhindered aryl bromides at room temperature in 2-propanol, while increasing the temperature to 60 degrees C allowed for the use of mono-or di-ortho-substituted aryl bromides. Oxidative addition of the aryl bromide was shown to proceed via a dissociative mechanism, implicating monoligated Pd(CNArDipp2) as the catalytically active intermediate. Attempts to access this fleeting species via activation of the Pd-II monoisocyanide PdCl(eta(3)-C3H5)(CNArDipp2) with alkoxide base yielded the dinuclear Pd-I species mu-C3H5(mu-O'Pr)[Pd(CNArDipp2)](2). Although dinuclear Pd-I complexes are often produced as off-cycle species when using complexes of the type PdCl(eta(3)-allyl)L as precatalysts, this represents the first time that the comproportionation product (mu-allyl)(mu-Cl)[PdL](2) has been observed to undergo nucleophilic substitution with alkoxide, despite the fact that activating conditions for these precatalysts typically employ alkoxide bases. Remarkably, this alkoxide complex can undergo, beta-hydride elimination with expulsion of acetone and propene to produce two equivalents of, catalytically active Pd(CNArDipp2), which can self-aggregate to yield the isolable tripalladium cluster Pd-3(eta(2)-Dipp-mu-CNArDipp2)(3). This cluster is catalytically competent for the Suzuki Miyaura reaction and functions as a formal source of monoligated Pd(CNArDipp2) in solution.

  DOI：

  10.1021/acs.organomet.7b00035

文献信息

• Synthetic and Mechanistic Interrogation of Pd/Isocyanide-Catalyzed Cross-Coupling: π-Acidic Ligands Enable Self-Aggregating Monoligated Pd(0) Intermediates
  作者：Brandon R. Barnett、Liezel A. Labios、Julia M. Stauber、Curtis E. Moore、Arnold L. Rheingold、Joshua S. Figueroa

  DOI：10.1021/acs.organomet.7b00035

  日期：2017.2.27

  Despite the large number of judiciously designed ligands that have been exploited in palladium-catalyzed cross-coupling protocols, the incorporation of ligands bearing appreciable pi-acidic properties has remained significantly underexplored. Herein, we demonstrate that well-defined and low-coordinate Pd-0 complexes supported by m-terphenyl isocyanides function as competent catalysts for the Suzuki Miyaura cross-coupling of aryl bromides and arylboronic acids. Two-coordinate Pd(CNArDiPP2)(2) was active for the coupling of unhindered aryl bromides at room temperature in 2-propanol, while increasing the temperature to 60 degrees C allowed for the use of mono-or di-ortho-substituted aryl bromides. Oxidative addition of the aryl bromide was shown to proceed via a dissociative mechanism, implicating monoligated Pd(CNArDipp2) as the catalytically active intermediate. Attempts to access this fleeting species via activation of the Pd-II monoisocyanide PdCl(eta(3)-C3H5)(CNArDipp2) with alkoxide base yielded the dinuclear Pd-I species mu-C3H5(mu-O'Pr)[Pd(CNArDipp2)](2). Although dinuclear Pd-I complexes are often produced as off-cycle species when using complexes of the type PdCl(eta(3)-allyl)L as precatalysts, this represents the first time that the comproportionation product (mu-allyl)(mu-Cl)[PdL](2) has been observed to undergo nucleophilic substitution with alkoxide, despite the fact that activating conditions for these precatalysts typically employ alkoxide bases. Remarkably, this alkoxide complex can undergo, beta-hydride elimination with expulsion of acetone and propene to produce two equivalents of, catalytically active Pd(CNArDipp2), which can self-aggregate to yield the isolable tripalladium cluster Pd-3(eta(2)-Dipp-mu-CNArDipp2)(3). This cluster is catalytically competent for the Suzuki Miyaura reaction and functions as a formal source of monoligated Pd(CNArDipp2) in solution.