53484-52-9Relevant academic research and scientific papers
Heck reactions in aqueous miniemulsions
Zayas, Hazit A.,Valade, David,Jia, Zhongfan,Monteiro, Michael J.
, p. 1090 - 1094 (2012)
Carrying out organic reactions in water-based nanoreactors represents a 'green' method for the preparation of organic compounds. This process eliminates the need for solvents, thus reducing the effect of high volumes of solvent on the environment. In this work, we demonstrate a successful Heck cross-coupling reaction, one of the most used approaches to form CC bonds using a palladium catalyst, in a miniemulsion. The miniemulsion droplet sizes were small (25 to 42nm), and the reactions resulted in high conversions of three different products with high trans stereoisomers.
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
supporting information, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
“TPG-lite”: A new, simplified “designer” surfactant for general use in synthesis under micellar catalysis conditions in recyclable water
Thakore, Ruchita R.,Takale, Balaram S.,Hu, Yuting,Ramer, Selene,Kostal, Jakub,Gallou, Fabrice,Lipshutz, Bruce H.
, (2021/04/22)
Using the oxidized, carboxylic acid-containing form of MPEG-750, esterification with racemic vitamin E affords a new surfactant (TPG-lite) that functions as an enabling, nanoreactor-forming amphiphile for use in many types of important reactions in synthesis. The presence of a single ester bond is suggestive of simplified treatment as a component of (eventual) reaction waste water, after recycling. Many types of reactions, including aminations, Suzuki-Miyaura, SNAr, and several others are compared directly with TPGS-750-M, leading to the conclusion that TPG-lite can function as an equivalent nanomicelle-forming surfactant in water. Prima facie evidence amassed via DLS and cryo-TEM analyses support these experimental observations. In silico evaluations of the aquatic toxicity and carcinogenicity of TPG-lite indicate that it is safe to use.
Non-Chelate-Assisted Palladium-Catalyzed Aerobic Oxidative Heck Reaction of Fluorobenzenes and Other Arenes: When Does the C?H Activation Need Help?
Albéniz, Ana C.,Villalba, Francisco
supporting information, p. 4795 - 4804 (2021/09/06)
The pyridone fragment in the ligand [2, 2’-bipyridin]-6(1H)-one (bipy-6-OH) enables the oxidative Heck reaction of simple arenes with oxygen as the sole oxidant and no redox mediator. Arenes with either electron-donating or electron-withdrawing groups can be functionalized in this way. Experimental data on the reaction with toluene as the model arene shows that the C?H activation step is turnover limiting and that the ligand structure is crucial to facilitate the reaction, which supports the involvement of the pyridone fragment in the C?H activation step. In the case of fluoroarenes, the alkenylation of mono and 1,2-difluoro benzenes requires the presence of bipy-6-OH. In contrast, this ligand is detrimental for the alkenylation of 1,3-difluoro, tri, tetra and pentafluoro benzenes which can be carried out using just [Pd(OAc)2]. This correlates with the acidity of the fluoroarenes, the most acidic undergoing easier C?H activation so other steps of the reaction such as the coordination-insertion of the olefin become kinetically important for polyfluorinated arenes. The use of just a catalytic amount of sodium molybdate as a base proved to be optimal in all these reactions. (Figure presented.).
Alkene Synthesis by Photo-Wolff-Kischner Reaction of Sulfur Ylides and N-Tosylhydrazones
Gao, Pan-Pan,Yan, Dong-Mei,Bi, Ming-Hang,Jiang, Min,Xiao, Wen-Jing,Chen, Jia-Rong
, p. 14195 - 14201 (2021/09/20)
A visible-light-driven and room temperature photo-Wolff-Kischner reaction of sulfur ylides and N-tosylhydrazones has been developed for the first time to provide modular access to alkene synthesis. The high functional group tolerance and broad substrate scope were demonstrated by more than 60 examples. Both E- and Z-olefinic stereochemistry in the products could be controlled with excellent stereoselectivity. A series of mechanistic studies support that the reaction should proceed through a radical-carbanion crossover pathway, specifically involving addition of photo-generated sulfur ylide radical cations to N-tosylhydrazones to form carbanions and subsequent Wolff-Kischner process.
Water-Sculpting of a Heterogeneous Nanoparticle Precatalyst for Mizoroki-Heck Couplings under Aqueous Micellar Catalysis Conditions
Pang, Haobo,Hu, Yuting,Yu, Julie,Gallou, Fabrice,Lipshutz, Bruce H.
supporting information, p. 3373 - 3382 (2021/04/07)
Powdery, spherical nanoparticles (NPs) containing ppm levels of palladium ligated by t-Bu3P, derived from FeCl3, upon simple exposure to water undergo a remarkable alteration in their morphology leading to nanorods that catalyze Mizoroki-Heck (MH) couplings. Such NP alteration is general, shown to occur with three unrelated phosphine ligand-containing NPs. Each catalyst has been studied using X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and cryogenic transmission electron microscopy (cryo-TEM) analyses. Couplings that rely specifically on NPs containing t-Bu3P-ligated Pd occur under aqueous micellar catalysis conditions between room temperature and 45 °C, and show broad substrate scope. Other key features associated with this new technology include low residual Pd in the product, recycling of the aqueous reaction medium, and an associated low E Factor. Synthesis of the precursor to galipinine, a member of the Hancock family of alkaloids, is suggestive of potential industrial applications.
Gelatin-pyrolyzed mesoporous N-doped carbon supported Pd as high-performance catalysts for aqueous Heck reactions
Yang, Shuai,Chen, Yuli,Huang, Shuaijian,Deng, Lu,Wu, Yuanyuan,Zheng, Xiu,Omonov, Shakhzodjon,Zeng, Minfeng
, (2021/05/19)
Nitrogen-doped mesoporous carbon-supported Pd (Pd@N-C) catalysts were prepared by pyrolyzing gelatin/templates/PdCl2 hydrogels under N2 atmosphere at 800°C. Using poly (ethylene glycol) block poly (propylene glycol) block poly (ethyl
Highly effective cellulose supported 2-aminopyridine palladium complex (Pd(II)-AMP-Cell?Al2O3) for Suzuki-Miyaura and Mizoroki–Heck cross-coupling
Mhaldar, Pradeep,Pore, Dattaprasad,Rashinkar, Gajanan,Vibhute, Sandip
, (2020/04/15)
In the present work, a novel, highly efficient, retrievable organo–inorganic hybrid heterogeneous catalyst (Pd(II)-AMP-Cell?Al2O3) has been prepared by covalent grafting of 2-aminopyridine on chloropropyl modified cellulose-alumina composite followed by complexation with palladium acetate. The catalyst was characterized by techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), inductive coupled plasma-atomic emission spectroscopy (ICP-AES) and thermo gravimetric analysis (TGA). The catalyst has been successfully employed in Suzuki-Miyaura as well as Mizoroki–Heck cross-coupling reactions. The reactions proceed smoothly resulting in the high yields of cross-coupling products (81 to 95%) within short reaction times. The catalyst can be efficiently recovered by simple filtration and reused for multiple cycles without considerable loss in the catalytic activity. The key-features of the present protocol include mild reaction conditions, simple work-up procedure, high stability of the catalyst, high turnover number (TON) and frequency (TOF), ease recovery and reusability of the catalyst.
Mono- and dinuclear palladium(II) complexes incorporating 1,2,3-triazole-derived mesoionic carbenes: syntheses, solid-state structures and catalytic applications
Zhang, Xin,Yan, Xuechao,Zhang, Bo,Wang, Ran,Guo, Shuai,Peng, Shiyong
, p. 39 - 48 (2018/08/06)
Two 1,2,3-triazole-derived monocationic salts 3 and 4 bearing N-aryl wingtips were prepared using copper-catalyzed “click” reactions followed by alkylations with iodomethane. Employing a silver–carbene transfer method, two dinuclear palladium(II) complexes of triazolin-5-ylidenes (5/6) were obtained, the former of which has been reported previously. Bridge-cleavage reaction of 5 as a representative with PPh3 yielded cis-configured mesoionic carbene/phosphine hybrid complex cis-7 and homoleptic bis(phosphine) complex 8, suggesting the presence of a ligand exchange process. In contrast, bridge breakages of 5/6 with pyridine cleanly afforded PEPPSI-type complexes 9 and 10 in near quantitative yields. Finally, all complexes were exploited to catalyze Mizoroki–Heck coupling reactions with aryl bromides as the substrates, and PEPPSI-type complex 9 was found to be the best performer generally giving good to excellent yields.
Mizoroki–Heck Cross-Coupling of Acrylate Derivatives with Aryl Halides Catalyzed by Palladate Pre-Catalysts
Islam, Mohammad Shahidul,Nahra, Fady,Tzouras, Nikolaos V.,Barakat, Assem,Cazin, Catherine S. J,Nolan, Steven P.,Al-Majid, Abdullah Mohammed
supporting information, p. 4695 - 4699 (2019/11/13)
The Mizoroki–Heck (MH) reaction involving aryl halides with various acrylates and acrylamides has been studied using air and moisture-stable imidazolium-based palladate pre-catalysts. These pre-catalysts can be converted into Pd-NHC species (NHC = N-heterocyclic carbene) under catalytic conditions and are capable of facilitating the Mizoroki–Heck reaction of aryl halides with various acrylates. The effects of solvent, catalyst loading, temperature and bases on the reaction outcome have been investigated. Various coupling partners were tolerated under the optimal reaction conditions catalyzed by palladate 1, [SIPr·H][Pd(η3-2-Me-allyl)Cl2]. The efficiency of the optimized synthetic methodology was tested on various aryl halides and substituted acrylates as well as acrylamides. The MH reaction yielded the coupled products in good to excellent isolated yields (up to 98%).
