Stereoelectronic Effects Characterizing Nucleophilic Carbene Ligands Bound to the Cp*RuCl (Cp* = η5-C5Me5) Moiety:  A Structural and Thermochemical Investigation

Huang, Jinkun; Schanz, Hans‐Joerg; Stevens, Edwin D.; Nolan, Steven P.

doi:10.1021/om990054l

Cited by 339 publications

(188 citation statements)

References 27 publications

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“…[34][35][36][37][38] The NHC ligands in these palladium catalysts are outstanding s-donors facilitating the oxidative reactions of aryl halides to the palladium center. [6,[39][40][41] Furthermore, these catalysts do not require the addition of excess ligand during the reaction. Finally, the NHC ligands enhance the elimination of the final product from the palladium center as a result of their bulky nature.…”

Section: Introductionmentioning

confidence: 99%

Poly(norbornene)‐Supported N‐Heterocyclic Carbenes as Ligands in Catalysis

Sommer

Weck

2006

Adv Synth Catal

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In this contribution, we present the synthesis of norbornene-supported N-heterocyclic (NHC) carbenes. These functionalized norbornenes were polymerized via ring-opening metathesis polymerization in a controlled fashion either before or after metalation with a variety of palladium and ruthenium precursors resulting in the formation of polymersupported NHC-based metal catalysts. The activities of the palladium-based catalysts in the SuzukiMiyaura, Sonogashira and Heck coupling reactions were studied in detail. In all cases, the polymeric catalysts demonstrated the same activity as their small molecule analogues. Furthermore, we carried out preliminary investigations into the stability of these catalysts using poisoning studies. A clear dependence of the stability of the polymer-supported catalysts on their palladium precursor was observed with palladium acetate-based polymeric NHC catalysts being the most stable. Finally, we have studied the reactivity of our supported NHC ruthenium complexes as catalysts for ring-closing metathesis. Again, in all cases good conversions were observed with comparable activities to other supported NHC-ruthenium catalysts. Lastly, we were able to remove the ruthenium catalysts from the solution quantitatively demonstrating the possibility of metal removal.

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Section: Introductionmentioning

confidence: 99%

Poly(norbornene)‐Supported N‐Heterocyclic Carbenes as Ligands in Catalysis

Sommer

Weck

2006

Adv Synth Catal

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“…Although carbenes are typically used as ligands for transition metals [11][12][13][14][15], or as nucleophilic organic catalysts [16][17][18][19][20][21][22][23][24][25], these carbene derivatives that contain an (H)CCl3 bound at the carbene C2 position have been found through reductive thermolysis, to give free carbene for reaction with metals [26].…”

Section: Synthetic Discussionmentioning

confidence: 99%

1,3-Bis(2,6-diisopropylphenyl)-2-trichloromethylimidazolidine

Stack

Masuda

2017

Molbank

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Abstract:A new chloroform adduct of the N-heterocyclic carbene (NHC) 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene (SIPr) has been prepared via C-H bond activation of the chloroform at the carbene carbon. This redox product was crystallized and was characterized by 1 H and 13 C-NMR spectroscopy, elemental analysis (EA), and single-crystal X-ray diffraction. The 1 H and 13 C-NMR spectroscopic data are in agreement with the crystal structure. Density functional theory (DFT) calculations were performed as a means for comparison to experimental data and the computational results are in agreement with those obtained experimentally.

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“…6 由于存在异丙基的 e 键稳定作用导致环己基不能翻转, 即不存在"柔韧翼", 使得 6 具有极大的空间位阻, 从而可以很好地保护卡宾碳和中心金属. 如果我们把膦配体比作一个"圆锥体", 把环二氨基卡宾比作一把"扇子" [25] , 那么 6 就像"一堵墙" [9] . …”

Section: Caacsunclassified

Cyclic(alkyl)(amino)carbenes and the Research Prospect in Olefin Metathesis Reaction

蔡援¹,

开铖²,

黄毅勇³

et al. 2014

Chin. J. Org. Chem.

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Olefin metathesis has been one of the most important methods to construct carbon-carbon double bonds, which has been enabled by development of well-defined transition-metal catalysts (e.g. [L 2 X 2 Ru＝CHR], L＝PCy 3 ). A significant gain to increase the catalyst stability and activity was achieved after replacing a single PCy 3 ligand of L 2 X 2 Ru＝CHR (L＝PCy 3 ) with cyclic biamino cabene, such as 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene (H 2 IMes). In 2005, Bertrand et al. discovered a novel ligand-yclic(alkyl)(amino)cabene (CAAC), which displayed more electron donating and more electrophilic in comparison with cyclic diamino cabene. It is logic that more electronegative amino group is replaced by alkyl group in CAAC. Furthermore, a quaternary carbon at the α position of carbene center of CAAC may make a big difference from cyclic diamino cabene, which can change the steric environment of CAAC easily and creat a chiral center next to the carbene. In this research prospect, synthesis, property and application of CAACs in olefin metathesis catalysis are introduced. Finally, the issues remained in this research area are summarized and an outlook for the development in the future is given.

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Stereoelectronic Effects Characterizing Nucleophilic Carbene Ligands Bound to the CpRuCl (Cp = η⁵-C₅Me₅) Moiety: A Structural and Thermochemical Investigation

Cited by 339 publications

References 27 publications

Poly(norbornene)‐Supported N‐Heterocyclic Carbenes as Ligands in Catalysis

Poly(norbornene)‐Supported N‐Heterocyclic Carbenes as Ligands in Catalysis

1,3-Bis(2,6-diisopropylphenyl)-2-trichloromethylimidazolidine

Cyclic(alkyl)(amino)carbenes and the Research Prospect in Olefin Metathesis Reaction

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