14064-41-6Relevant academic research and scientific papers
Rh-catalyzed reagent-free ring expansion of cyclobutenones and benzocyclobutenones
Chen, Peng-Hao,Sieber, Joshua,Senanayake, Chris H.,Dong, Guangbin
, p. 5440 - 5445 (2015)
Here we report a reagent-free rhodium-catalyzed ring-expansion reaction via C-C cleavage of cyclobutenones. A variety of poly-substituted cyclopentenones and 1-indanones can be synthesized from simple cyclobutenones and benzocyclobutenones. The reaction condition is near pH neutral without additional oxidants or reductants. The potential for developing a dynamic kinetic asymmetric transformation of this reaction has also been demonstrated. Further study supports the proposed pathway involving Rh-insertion into the cyclobutenone C-C bond, followed by β-hydrogen elimination, olefin insertion and reductive elimination.
Geometry constrained N-(5,6,7-trihydroquinolin-8-ylidene)arylaminopalladium dichloride complexes: Catalytic behavior toward methyl acrylate (MA), methyl acrylate-co-norbornene (MA-co-NB) polymerization and heck coupling
Zeng, Yanning,Mahmood, Qaiser,Liang, Tongling,Sun, Wen-Hua
, (2016)
A new pair of plladium complexes (Pd4 and Pd5) ligated with constrained N-(5,6,7-trihydroquinolin-8-ylidene)arylamine ligands have been prepared and well characterized by 1H-, 13C-NMR and FTIR spectroscopies as well as elemental analysis. The molecular structure of Pd4 and Pd5 in solid state have also been determined by X-ray diffraction, showing slightly distorted square planar geometry around the palladium metal center. All complexes Pd1-Pd5 are revealed highly efficient catalyst in methyl acrylate (MA) polymerization as well as methyl acrylate/norbornene (MA/NB) copolymerization. In the case of MA polymerization, as high as 98.4% conversion with high molecular weight up to 6282 kg·mol-1 was achieved. Likewise, Pd3 complex has good capability to incorporate about 18% NB content into MA polymer chains. Furthermore, low catalyst loadings (0.002 mol %) of Pd4 or Pd5 are able to efficiently mediate the coupling of haloarenes with styrene affording up to 98% conversion.
Synthesis of pincer-type N-heterocyclic carbene palladium complexes with a hemilabile ligand and their application in cross-coupling catalysis
Leigh, Vivienne,Ghattas, Wadih,Mueller-Bunz, Helge,Albrecht, Martin
, p. 33 - 39 (2014)
Benzimidazolium salts containing both a neutral imine and a masked carboxylate functional group for potential metal chelation were prepared. Palladation of the ester-protected ligand afforded a N,C-bidentate carbene complex 4. Subsequent ester hydrolysis preserved the bidentate coordination mode and yielded complex 5 with a pending COOH group exclusively. However, when ester deprotection was carried out prior to metalation, the N,C,O-tridentate pincer-type coordinated palladium complex 7 was obtained. Proton-abstraction of the dangling COOH group in the bidentate ligand of complex 5 by treatment with a base led to the formation of the N,C,O-tridentate coordinated Pd system 7, and inversely, exposure of the tridentate bound Pd complex 7 with acid afforded the N,C-bidentate ligand coordination mode in complex 5, demonstrating hemilability of the oxygen donor site in the pincer ligand. All three palladium(II) complexes 4, 5, and 7 were evaluated in cross-coupling catalysis and revealed distinct activity differences that are dependent on the type of coupling (Suzuki vs. Heck) and the substrate (Ar-Br vs. Ar-Cl). These differences suggest that judicious choice of donor groups in pincer-type complexes is a viable strategy for catalyst optimization.
Catalytic application of zwitterionic palladium complexes in Mizoroki-Heck reactions using ionic liquid as solvent
Wang, Yi-Ping,Lee, Hon Man
, p. 90 - 98 (2015)
New ligand precursors with different pendent alky chain length were obtained in a single step by reacting appropriate 1-alkyl-2-methyl-1H-imidazoles with chloroacetone in THF at 80°C overnight. Zwitterionic palladium complexes were prepared by reacting Pd
METHODS OF ARENE ALKENYLATION
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Page/Page column 18; 21-22; 42-43; 49, (2021/11/26)
The present disclosure provides for a rhodium-catalyzed oxidative arene alkenylation from arenes and styrenes to prepare stilbene and stilbene derivatives. For example, the present disclosure provides for method of making arenes or substituted arenes, in particular stilbene and stilbene derivatives, from a reaction of an optionally substituted arene and/or optionally substituted styrene. The reaction includes a Rh catalyst or Rh pre-catalyst material and an oxidant, where the Rh catalyst or Rh catalyst formed Rh pre-catalyst material selectively functionalizes CH bond on the arene compound (e.g., benzene or substituted benzene).
Synthesis of N-Heterocyclic Carbine Silver(I) and Palladium(II) Complexes with Acylated Piperazine Linker and Catalytic Activity in Three Types of C—C Coupling Reactions
Liu, Qingxiang,Zhang, Xiantao,Zhao, Zhixiang,Li, Xinying,Zhang, Wei
supporting information, p. 605 - 613 (2021/02/01)
Two bis-imidazolium salts LH2·Cl2 and LH2·(PF6)2 with acylated piperazine linker and two N-heterocyclic carbene (NHC) silver(I) and palladium(II) complexes [L2Ag2](PF6)2 (1) and [L2Pd2Cl4] (2) were prepared. The crystal structures of LH2·Cl2 and 1 were confirmed by X-ray analysis. In 1, one 26-membered macrometallocycle was generated through two silver(I) ions and two bidentate ligands L. The catalytic activity of 2 was investigated in Sonogashira, Heck-Mizoroki and Suzuki-Miyaura reactions. The results displayed that these C—C coupling reactions can be smoothly carried out under the catalysis of 2.
Tandem Acceptorless Dehydrogenative Coupling-Decyanation under Nickel Catalysis
Babu, Reshma,Balaraman, Ekambaram,Midya, Siba P.,Subaramanian, Murugan,Yadav, Vinita
, p. 7552 - 7562 (2021/06/28)
The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C=C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.
Stereospecific Iron-Catalyzed Carbon (sp2)-Carbon (sp2) Cross-Coupling of Aryllithium with Vinyl Halides
Chen, Peng,Peng, Xiao-Shui,Wang, Zhi-Yong,Wong, Henry N. C.
supporting information, p. 4385 - 4390 (2021/06/27)
We present herein an efficient synthetic protocol involving iron-catalyzed cross-coupling of organolithium compounds with vinyl halides as key coupling partners. More than 30 examples were obtained with moderate to good yields and high stereoselectivities. The practicality of this method is evidenced by a gram-scale synthesis. In addition, a preliminary mechanistic investigation was also performed.
Custom-Made Pyrene Photocatalyst-Promoted Desulfonylation of Arylethenyl Sulfones Using Green-Light-Emitting Diodes
Watanabe, Hikaru,Nakajima, Kazuki,Ekuni, Kento,Edagawa, Ryota,Akagi, Yuta,Okuda, Yasuhiro,Wakamatsu, Kan,Orita, Akihiro
, p. 2984 - 2994 (2021/03/04)
The Sonogashira coupling of 1,3,6,8-tetrabromopyrene with 4-[(-)-β-citronellyloxy]phenylethyne was employed to synthesize 1,3,6,8-tetra[4-(citronellyloxy)phenylethynyl]pyrene. The pyrene derivative catalyzed the reductive desulfonylation of ethenyl sulfones via visible-light irradiation (514 nm green light-emitting diodes) in the presence of i -Pr 2NEt. The β-citronellyloxy groups provided the sufficient solubility to the highly π-expanded pyrene catalyst, and their polar oxygen functionalities enabled the easy separation of the catalyst from the products via column chromatography.
Efficient photocatalytic chemoselective and stereoselective C-C bond formation over AuPd@N-rich carbon nitride
Jiang, Heyan,Xu, Jie,Zhang, Sishi,Cheng, Hongmei,Zang, Cuicui,Bian, Fengxia
, p. 219 - 229 (2021/01/28)
Heterogeneous chemoselective or stereoselective C-C coupling reactions remain extremely challenging in traditional organic synthesis. Here, we constructed a AuPd@N-rich carbon nitride (NRCN) photocatalyst through simple ammonia solution heat treatment of carbon nitride and then AuPd NP loading. AuPd@NRCN exhibited extraordinary light color promoted catalytic performance in C-C bond formation under visible light in air. Surprisingly, both high chemoselectivity to unsymmetrical Ullmann biaryl products and satisfactory stereoselectivity to Z-type Heck reaction products could be achieved by changing the light source color. Various substrates exhibited great potential for the economical synthesis of unsymmetrical biaryl products and Z-type olefins. Efficient visible light promoted C-I bond activation accompanied with improved photocatalytic coupling reaction efficiency over AuPd@NRCN was verified firstly by in situ DRIFTS. Considering that the Ullmann cross-coupling reaction is a multi-photon reaction, the improved photocatalytic performance in the Ullmann cross-coupling reaction using a combination of light sources with different colors might be due to the activation of different substrates and/or steps requiring different energies, and the combination of the two energy sources was beneficial for improving the activation efficiency of different substrates and/or steps. The activation of iodobenzene and styrene in the Heck reaction with light was also beneficial to the formation of the stilbene product. The light color promoted chemoselectivity and stereoselectivity are expected to have profound impact on organic synthetic methodology improvement. This journal is
