Rationally Designed Pincer-Type Heck Catalysts Bearing Aminophosphine Substituents: Pd<sup>IV</sup>Intermediates and Palladium Nanoparticles
作者:Jeanne L. Bolliger、Olivier Blacque、Christian M. Frech
DOI:10.1002/chem.200800441
日期:2008.9.8
catalytic cycle of the Heck reaction, their general existence as reactive intermediates (for example, in other reactions) cannot be excluded. On the contrary, they were shown to be thermally accessible. Compounds 1 and 2 show a smooth halideexchange with bromobenzene to yield their bromo derivatives in DMF at 100 degrees C. Experimental observations revealed that the halideexchange most probably proceeded
氨基膦基钳形配合物[C6H3-2,6-(XP(哌啶基)2)2Pd(Cl)](X = NH 1; X = O 2)可以很容易地由廉价的起始原料通过依次添加1,1在“一锅”中,在N 2下,将',1''-膦三基三哌啶和1,3-二氨基苯或间苯二酚制得[Pd(cod)(Cl)2](cod =环辛二烯)在甲苯中的溶液。事实证明,化合物1和2是出色的Heck催化剂,可以在很短的反应时间和较低的催化剂负载量下,在140℃下将数种电子失活和空间位阻的芳基溴化物与各种烯烃作为偶联伴侣进行定量偶联。升高的反应温度还使得在仅0.01mol%的催化剂存在下,烯烃能够与电子失活的和位阻的芳基氯有效地偶联。进行的机理研究排除了均相的Pd 0配合物是1和2的催化活性形式。另一方面,钯纳米颗粒参与催化循环得到了有力的实验支持。即使衍生自1(和2)的钳型Pd IV中间体不参与Heck反应的催化循环,也不能排除它们作为反应性中
Palladium(II)-catalyzed catalytic aminocarbonylation and alkoxycarbonylation of terminal alkynes: regioselectivity controlled by the nucleophiles
作者:Rami Suleiman、Jimoh Tijani、Bassam El Ali
DOI:10.1002/aoc.1585
日期:——
the selectivity towards the gem or trans unsaturated esters or amides with these nucleophiles. The effects of the type of palladium catalysts, the type of ligands, the amount of dppb and the solvents were carefully studied. With diisobutylamine (2b1), excellent regioselectivity towards the 2‐acrylamides (gem isomer, 3ab1) was almost always observed, while trans‐α,β‐unsaturated esters 4ac1 was the predominant
Pd(II)—dppb and syngas catalyze regioselective hydroesterification of terminal alkynes under neutral conditions
作者:Bassam El Ali、Jimoh Tijani、Abdel Moneim El-Ghanam
DOI:10.1016/s0040-4039(01)00152-6
日期:2001.3
Palladium(II) regioselectively catalyzes the hydroesterification of terminalalkynesunder syngas forming α,β-unsaturated esters 3 and 4 in excellent chemical yields under neutral conditions. The high selectivity for the linear ester 4 was obtained with a catalytic system that includes Pd(II), 1,4-bis(diphenylphosphino)butane (dppb) and CO/H2 in CH2Cl2 as solvent. The control of the regioselectivity
在中性条件下,钯(II)在合成气中区域选择性地催化末端炔烃的加氢酯化反应,形成出色的化学收率的α,β-不饱和酯3和4。通过在包括CH 2 Cl 2的溶剂中包含Pd(II),1,4-双(二苯基膦基)丁烷(dppb)和CO / H 2的催化体系获得对线性酯4的高选择性。区域选择性的控制在很大程度上取决于配体的类型,溶剂和合成气混合物的使用。
The role of phosphine ligands in the catalytic systems of the Heck reaction with aromatic carboxylic anhydrides
作者:N. A. Lagoda、E. V. Larina、E. V. Yarosh、A. A. Kurokhtina、A. F. Schmidt
DOI:10.1007/s11172-019-2490-7
日期:2019.4
phosphine-containing and phosphine-free catalytic systems of the Heckreactionusing aromatic carboxylic anhydrides as arylating agents are presented. It was demonstrated that the patterns of diff erential selectivity of the reaction under competition of two aromatic anhydrides or two alkenes are independent of the presence of a tertiary phosphine additive in the system. It was established that palladium complexes
A variety of chiral and achiral imidazoliumsalts is synthesized. Methylene-, ethylene-, propylene- and pyridinyl-bridged bis(imidazolium) halides are used to generate the respective free chelating carbenes. The synthesis of palladium complexes of general formula [cis-CH 2 NC(H)=C(H)N(R)C} 2 PdX 2 ] with these chelating N-heterocyclic carbene ligands is reported. Structural proofs of complexes 28