- Implications for multidimensional effects on isomerization dynamics: Photoisomerization study of 4,4'-dimethylstilbene in n-alkane solvents
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Studies of the photoisomerization of 4,4'-dimethylstilbene in n-alkane solvents are reported.As with similar studies it is possible to identify an activation barrier to isomerization and the viscosity dependence of the isomerization is not adequately expl
- Park, N. S.,Waldeck, D. H.
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- Efficient preparation method of symmetric diarylethene compound
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The invention belongs to the technical field of fine chemicals and related chemistry, and provides an efficient preparation method of a symmetric diarylethene compound. The method comprises the following steps: with halomethyl-containing aromatic hydrocarbon and derivatives thereof as raw materials, conducting reacting at 100 DEG C for 12 hours in the presence of a catalyst, alkali, additives andan anhydrous organic solvent so as to obtain the corresponding diarylethene compound with symmetry. The method has the beneficial effects that no transition metal reaction exists, reaction conditionsare mild, operation is simple and convenient, the possibility of industrialization is realized, and the diarylethene compound is obtained at high yield; and the diarylethene compound synthesized by using the method can be further functionalized to obtain various compounds, and is applied to development and research of natural products, functional materials and fine chemicals.
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Paragraph 0050-0052
(2021/02/10)
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- N-Heterocyclic carbene palladium (II)-pyridine (NHC-Pd (II)-Py) complex catalyzed heck reactions
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A mild, efficient, and practical catalytic system for the synthesis of highly privileged stilbene pharmacophores is reported. This system uses N-heterocyclic carbene palladium (II) Pyridine (NHC-Pd (II)-Py) complex to catalyze the formation of carbon-carbon bonds between olefin derivatives and various bromide. This simple, gentle and user-friendly method can offer a variety of stilbene products in excellent yields under solvent-free condition. And its scale-up reaction has excellent yield and this system can be applied to industrial fields. The utility of this method is highlighted by its universality and modular synthesis of a series of bioactive molecules or important medical intermediates.
- Li, Dan,Tian, Qingqiang,Wang, Xuetong,Wang, Qiang,Wang, Yin,Liao, Siwei,Xu, Ping,Huang, Xin,Yuan, Jianyong
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supporting information
p. 2041 - 2052
(2021/05/25)
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- AIR-STABLE NI(0)-OLEFIN COMPLEXES AND THEIR USE AS CATALYSTS OR PRECATALYSTS
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The present invention relates to air stable, binary Ni(0)-olefin complexes and their use in organic synthesis.
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Page/Page column 13; 15
(2021/02/05)
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- Energy-Transfer-Mediated Photocatalysis by a Bioinspired Organic Perylenephotosensitizer HiBRCP
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Energy transfer plays a special role in photocatalysis by utilizing the potential energy of the excited state through indirect excitation, in which a photosensitizer determines the thermodynamic feasibility of the reaction. Bioinspired by the energy-transfer ability of natural product cercosporin, here we developed a green and highly efficient organic photosensitizer HiBRCP (hexaisobutyryl reduced cercosporin) through structural modification of cercosporin. After structural manipulation, its triplet energy was greatly improved, and then, it could markedly promote the efficient geometrical isomerization of alkenes from the E-isomer to the Z-isomer. Moreover, it was also effective for energy-transfer-mediated organometallic catalysis, which allowed realization of the cross-coupling of aryl bromides and carboxylic acids through efficient energy transfer from HiBRCP to nickel complexes. Thus, the study on the relationship between structural manipulation and their photophysical properties provided guidance for further modification of cercosporin, which could be applied to more meaningful and challenging energy-transfer reactions.
- Zhang, Yan,Xia, Mingze,Li, Min,Ping, Qian,Yuan, Zhenbo,Liu, Xuanzhong,Yin, Huimin,Huang, Shuping,Rao, Yijian
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p. 15284 - 15297
(2021/11/01)
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- Synthesis, crystal structure, and catalytic activity of bridged-bis(N-heterocyclic carbene) palladium(II) complexes in selective Mizoroki-Heck cross-coupling reactions
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A series of three 1,3-propanediyl bridged bis(N-heterocyclic carbene)palladium(II) complexes (Pd-BNH1, Pd-BNH2, and Pd-BNH3), with + I effect order of the N-substituents of the ligand (isopropyl > benzyl > methoxyphenyl), was the subject of a spectroscopic, structural, computational and catalytic investigation. The bis(NHC)PdBr2 complexes were evaluated in Mizoroki-Heck coupling reactions of aryl bromides with styrene or acrylate derivatives and showed high catalytic efficiency to produce diarylethenes and cinnamic acid derivatives. The X-ray structure of the most active palladium complex Pd-BNH3 shows that the Pd(II) center is bonded to the two carbon atoms of the bis(N-heterocyclic carbene) and two bromide ligands in cis position, resulting in a distorted square planar geometry. The NMR data of Pd-BNH3 are consistent with a single chair-boat rigid conformer in solution with no dynamic behavior of the 8-membered ring palladacycle in the temperature range 25–120 °C. The catalytic activities of three Pd-bridged bis(NHC) complexes in the Mizoroki-Heck cross-coupling reactions were not found to have a direct correlation with +I effect order of the N-substituents of the ligand. However, a direct correlation was found between the DFT calculated absolute softness of the three complexes with their respective catalytic activity. The highest calculated softness, in the case of Pd-BNH3, is expected to favor the coordination steps of both the soft aryl bromides and alkenes in the Heck catalytic cycle.
- El Ali, Bassam,Fettouhi, Mohammed,Iali, Wissam,Mansour, Waseem,Suleiman, Rami
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- Palladium nanoparticlesin situsynthesized onCyclea barbatapectin as a heterogeneous catalyst for Heck coupling in water, the reduction of nitrophenols and alkynes
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This study develops an effective method for thein situsynthesis of palladium nanoparticles (PdNPs) usingCyclea barbatapectin as a green reducing and stabilizing reagent. The PdNP@pectin nanocomposite was well characterized by analysis techniques such as UV-vis, FTIR, EDX, XRD, SEM, HR-TEM and STEM-mapping. Crystalline PdNPs were found to be distributed in the size range of 1-25 nm with the highest frequency of 6-12 nm. PdNP@pectin exhibited excellent recyclable catalysis activity for the Heck coupling reaction in water medium. The kinetics and recyclability of nanoparticles were investigated for the catalytic reduction ofo-,m- andp-nitrophenol. The result showed a good catalysis efficiency with five successful recycles without compromising much. In particular, the nanocomposite was used as a catalyst for the conversion of alkynes intocis-alkenes with KOH/DMF as a hydrogenation source. The reaction was also utilized effectively for the synthesis of sex pheromones, includingPlutella xylostella((Z)-11-hexadecen-1-yl acetate) andCylas formicarius((Z)-3-dodecen-1-yl(E)-2-butenoate) with the total yields of 70% and 68%, respectively. Therefore, PdNPs supported onC. barbatapectin are promising catalysis materials for application in various fields.
- Le, Van-Dung,Le, T. Cam-Huong,Chau, Van-Trung,Le, T. Ngoc-Duyen,Dang, Chi-Hien,Vo, T. To-Nguyen,Nguyen, Trinh Duy,Nguyen, Thanh-Danh
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p. 4746 - 4755
(2021/03/22)
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- Method for reducing alkyne into olefin by taking water as hydrogen source under catalysis of nickel
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The invention discloses a method for reducing alkyne into olefin by taking water as a hydrogen source under the catalysis of nickel, which comprises the following steps: placing alkyne in a solvent to react under the action of a nickel catalyst, a ligand, alkali, a boron reagent and a hydrogen source, and carrying out post-treatment to obtain olefin, and the hydrogen source is water. According to the invention, a cheap metal nickel catalyst is combined with a boron reagent to activate water, so that hydrogen transfer is realized, and the use of dangerous hydrogen is avoided. The method has good stereoselectivity, no excessive hydrogenation product alkane is generated, conditions are mild, the highest yield can reach 99%, and the method has good application prospects.
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Paragraph 0067-0070
(2021/06/26)
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- Tandem Acceptorless Dehydrogenative Coupling-Decyanation under Nickel Catalysis
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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.
- Babu, Reshma,Balaraman, Ekambaram,Midya, Siba P.,Subaramanian, Murugan,Yadav, Vinita
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p. 7552 - 7562
(2021/06/28)
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- PVC-NHC-Pd(0): An efficient and reusable heterogeneous catalyst for highly cis-selective semihydrogenation of alkynes using formic acid as hydrogen source
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PVC-NHC-Pd(0) catalyst was prepared and exerted to highly cis-selective semihydrogenation of diarylacetylene using formic acid as hydrogen source under mild condition. The as-prepared catalyst was well characterized by various techniques such as FT-IR, 1H NMR, XRD, SEM, EDX, TEM, XPS, and TGA. The catalyst can be easily recovered and recycled without loss of its activity and selectivity owing to the metal-ligand interaction between Pd(0) with polymeric NHC ligands. This protocol is an attractive alternative of the classical Lindlar's hydrogenation.
- Li, Yiqun,Zheng, Waner,Zhou, Yuemin
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- Palladium Complexes with Phenoxy- And Amidate-Functionalized N-Heterocyclic Carbene Ligands Based on 3-Phenylimidazo[1,5- a]pyridine: Synthesis and Catalytic Application in Mizoroki-Heck Coupling Reactions with Ortho-Substituted Aryl Chlorides
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Mononuclear and tetranuclear palladium complexes with functionalized "abnormal"N-heterocyclic carbene (aNHC) ligands based on 3-phenylimidazo[1,5-a]pyridine were synthesized. All of the new complexes were structurally characterized by single-crystal X-ray diffraction studies. The new complexes were applied in the Mizoroki-Heck coupling reaction of aryl chlorides with alkenes in neat n-tetrabutylammonium bromide (TBAB). The mononuclear palladium complex with a tridentate phenoxy- and amidate-functionalized aNHC ligand displayed activity superior to that of the palladium complex with a bidentate amidate-functionalized aNHC ligand. The new tetranuclear complex with the tridentate ligand displayed the best activities, capable of the activation of deactivated aryl chlorides as substrates with a low Pd atom loading. Even challenging sterically demanding ortho-substituted aryl chlorides were successfully utilized as substrates. The studies revealed that the robustness of the catalyst precursor is crucial in delivering high catalytic activities. Also, the promising use of tetranuclear palladium complexes with functionalized aNHC ligands as the catalyst precursors in the Mizoroki-Heck coupling reaction in neat TBAB was demonstrated.
- Hung, Cheng-Hau,Zheng, Wei-Yuan,Lee, Hon Man
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p. 702 - 713
(2021/04/02)
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- Selenenate Anions (PhSeO?) as Organocatalyst: Synthesis of trans-Stilbenes and a PPV Derivative
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The selenenate anion (RSeO?) is introduced as an active organocatalyst for the dehydrohalogen coupling of benzyl halides to form trans-stilbenes. It is shown that RSeO? is a more reactive catalyst than the previously reported sulfur analogues (sulfenate anion, RSO?) and selenolate anions (RSe?) in the aforementioned reaction. This catalytic system was also applied to the benzylic-chloromethyl-coupling polymerization (BCCP) of a bis-chloromethyl arene to form ppv (poly(p-phenylene vinylene))-type polymers with high yields, Mn (average molecular weight) up to 13,000 and ? (dispersity) of 1.15. (Figure presented.).
- Zheng, Zhipeng,Trofymchuk, Oleksandra S.,Kurogi, Takashi,Varela, Elena,Mindiola, Daniel J.,Walsh, Patrick J.
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supporting information
p. 659 - 666
(2020/01/02)
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- An Annelated Mesoionic Carbene (MIC) Based Ru(II) Catalyst for Chemo- And Stereoselective Semihydrogenation of Internal and Terminal Alkynes
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The catalytic utility of [RuL1(CO)2I2] (1), containing an annelated π-conjugated imidazo-naphthyridine-based mesoionic carbene (MIC) ligand (L1), is evaluated for E-selective alkyne semihydrogenation. The precatalyst 1, in combination with 2 equiv of AgBArF, semihydrogenates a broad range of internal alkynes with molecular hydrogen (5 bar) in water. (E)-Alkenes are accessed in high yields, and a number of reducible functional groups are tolerated. A chelate MIC ligand and two cis carbonyls provide a well-defined platform at the Ru center for hydrogenation and isomerization. The loss of two iodides and the presence of two carbonyls render the Ru center electron deficient and thus the formation of metal vinylidenes with terminal alkynes is avoided. This is leveraged for the semihydrogenation of terminal alkynes by the same catalytic system in isopropyl alcohol. Reaction profile, isomerization, kinetic, and DFT studies reveal initial alkyne hydrogenation to a (Z)-alkene, which further isomerizes to an (E)-alkene via metal-catalyzed Z → E isomerization.
- Bera, Jitendra K.,Choudhury, Joyanta,Das, Shubhajit,Dutta, Indranil,Pati, Swapan K.,Saha, Sayantani,Yadav, Suman
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p. 3212 - 3223
(2020/10/02)
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- Tuning the Selectivity of Palladium Catalysts for Hydroformylation and Semihydrogenation of Alkynes: Experimental and Mechanistic Studies
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Here, we describe a selective palladium catalyst system for chemodivergent functionalization of alkynes with syngas. In the presence of an advanced ligand L2 bearing 2-pyridyl substituent as a built-in base, either hydroformylation or semihydrogenation of diverse alkynes occurs with high chemo- and stereoselectivity under comparable conditions. Mechanistic studies, including density functional theory (DFT) calculations, kinetic analysis, and control experiments, revealed that the strength and concentration of acidic cocatalysts play a decisive role in controlling the chemoselectivity. DFT studies disclosed that ligand L2 not only promotes heterolytic activation of hydrogen similar to frustrated Lewis pair (FLP) systems in the hydrogenolysis step for hydroformylation but also suppresses CO coordination to promote semihydrogenation under strong acid conditions. This switchable selectivity provides a strategy to design new catalysts for desired products.
- Beller, Matthias,Ge, Yao,Jackstell, Ralf,Jiao, Haijun,Liu, Jiawang,Wei, Duo,Wei, Zhihong,Yang, Ji
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p. 12167 - 12181
(2020/11/27)
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- Ni(4?Tbustb)3: A robust 16-electron Ni(0) olefin complex for catalysis
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Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis of a unique family of tris Ni(0) stilbene complexes revealed a remarkable effect of the steric hindrance of the substituents at the para position of the stilbene unit to temperature, oxidation, and degradation in solution. From these analyses, Ni(4?tBustb)3 arose as a long-term air-, bench-. and temperature-stable Ni(0) complex. Importantly, Ni(4?tBustb)3 presents faster kinetic profiles and a broader scope as a Ni(0) source, thus outperforming the previously described Ni(4?CF3stb)3 in a variety of relevant Ni-catalyzed transformations.
- Nattmann, Lukas,Cornella, Josep
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supporting information
p. 3295 - 3300
(2020/10/12)
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- E, Z -Selectivity in the reductive cross-coupling of two benzaldehydes to stilbenes under substrate control
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Unsymmetrical E- and Z-stilbenes can be synthesized from two differently substituted benzaldehydes in a MesP(TMS)Li-promoted reductive coupling sequence. Depending on the order of addition of the two coupling partners, the same olefin can be produced in either E- or Z-enriched form under identical reaction conditions. A systematic study of the correlation between the stereochemical outcome of the reaction and the substitution pattern at the two aldehydes is presented. The results can be used as guidelines to predict the product stereochemistry. This journal is
- Arkhypchuk, Anna I.,D'Imperio, Nicolas,Ott, Sascha
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supporting information
p. 6171 - 6179
(2020/10/21)
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- Palladium-Catalyzed Mizoroki-Heck Reaction of Nitroarenes and Styrene Derivatives
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We have developed a Mizoroki-Heck reaction of nitroarenes with alkenes under palladium catalysis. The use of a Pd/BrettPhos catalyst promoted the alkenylation, whereas other catalysts led to a decrease in the product yield. In addition to nitroarenes, nitroheteroarenes were also applicable to the present reaction. The combination of a nucleophilic aromatic substitution (SNAr) with the denitrative alkenylation produced a multifunctionalized arene in a one-pot operation.
- Okita, Toshimasa,Asahara, Kitty K.,Muto, Kei,Yamaguchi, Junichiro
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supporting information
p. 3205 - 3208
(2020/04/10)
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- Iodine-catalysed transfer hydrogenation of a carbon-carbon σ-bond with water
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Iodine catalysed the transfer hydrogenation of a benzylic C-C σ-bond in [2.2]paracyclophane with water to yield 4,4′-dimethylbibenzyl. The C-C σ-bond was first cleaved by homolytic substitution with iodine radicals to produce a 4,4′-diiodomethylbibenzyl i
- Yang, Wu,To, Ching Tat,Chan, Kin Shing
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supporting information
p. 6757 - 6761
(2019/07/22)
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- Synthesis of [7]Helicene Enantiomers and Exploratory Study of Their Conversion into Helically Chiral Iodoarenes and Iodanes
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The facile and convenient preparation of both enantiomers of a [7]helicene scaffold from inexpensive (l)-(+)-tartaric acid and 4-methylstyrene is described. These helical structures were transformed into bis-iodinated ether derivatives in order to explore their potential as precursors of novel chiral organoiodane reagents or as iodoarene pre-catalysts. Promising results were obtained in hydroxylative phenol dearomatization/[4+2] cycloaddition cascade and dearomative spirolactonization reactions with encouraging enantiomeric excesses.
- Antien, Kevin,Pouységu, Laurent,Deffieux, Denis,Massip, Stéphane,Peixoto, Philippe A.,Quideau, Stéphane
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supporting information
p. 2852 - 2858
(2019/02/05)
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- Catalytic Transfer Hydrogenation Using Biomass as Hydrogen Source
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We developed an operationally simple method for the direct use of biomass-derived chemical entities in a fundamentally important process, such as hydrogenation. Various carbohydrates, starch, and lignin were used for stereoselective hydrogenation. Employing a transition metal catalyst and a novel catalytic system, the reduction of alkynes, alkenes, and carbonyl groups with high yields was demonstrated. The regioselective hydrogenation to access different stereoisomers was established by simple variations in the reaction conditions. This work is based on an unprecedented catalytic system and represents a straightforward application of biomass as a reducing reagent in chemical reactions.
- Antonchick, Andrey P.,Manna, Srimanta
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p. 3094 - 3098
(2018/09/14)
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- Palladium(ii) ligated with a selenated (Se, CNHC, N-)-type pincer ligand: An efficient catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling in water
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A new 1-[N-benzylacetamido]-3-[1-(2-phenylselenylethyl)]benzimidazolium chloride (L), the precursor of a novel (Se, CNHC, N-)-type pincer ligand (L) was synthesised in high yield through a sequence of consecutive reactions of 1H-benzimidazole with ethylene dichloride, sodium selenophenolate, and N-benzyl-2-chloroacetamide. The palladium-promoted reaction of L with PdCl2 resulted in a moisture- and air-insensitive complex [Pd(L-H2Cl)Cl] (1), which demonstrated outstanding catalytic potential for Mizoroki-Heck coupling of aromatic bromides and chlorides (with yields up to 94% and 70%, respectively) at very low catalyst loading (0.2 mol%) and under mild reaction conditions in water. The complex (1) was also investigated for Suzuki-Miyaura coupling and found to be selectively efficient (yields up to 94%) for Suzuki-Miyaura coupling of aromatic bromides at 0.01 mol% of 1 in water. All coupling reactions were carried out in the green and economical solvent, water, which is highly desirable for bulk synthesis of complex molecules in industry. During the catalytic process, complex 1 converted into PdSe nanoparticles (NPs, size range 5-6 nm) in situ. The morphology and composition of these NPs were analysed through high-resolution transmission electron microscopy and transmission electron microscopy-energy dispersive X-ray spectroscopy, respectively. The core-level, X-ray photoelectron spectroscopy analysis confirmed the presence of stable Pd0 and Pd2+ oxidation states in these PdSe NPs. Based on further experimental investigations, these nanoparticles were found to work as a stock of true catalytic species. The hot filtration test, as well as the two-phase test, confirmed the largely homogeneous nature of the catalytic process, which probably proceeds by leaching of solution-phase Pd species from these NPs.
- Sharma, Kamal Nayan,Satrawala, Naveen,Srivastava, Avinash Kumar,Ali, Munsaf,Joshi, Raj Kumar
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p. 8969 - 8976
(2019/10/28)
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- Photoinitiated carbonyl-metathesis: Deoxygenative reductive olefination of aromatic aldehydes: Via photoredox catalysis
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Carbonyl-carbonyl olefination, known as McMurry reaction, represents a powerful strategy for the construction of olefins. However, catalytic variants that directly couple two carbonyl groups in a single reaction are less explored. Here, we report a photoredox-catalysis that uses B2pin2 as terminal reductant and oxygen trap allowing for deoxygenative olefination of aromatic aldehydes under mild conditions. This strategy provides access to a diverse range of symmetrical and unsymmetrical alkenes with moderate to high yield (up to 83%) and functional-group tolerance. To follow the reaction pathway, a series of experiments were conducted including radical inhibition, deuterium labelling, fluorescence quenching and cyclic voltammetry. Furthermore, NMR studies and DFT calculations were combined to detect and analyze three active intermediates: a cyclic three-membered anionic species, an α-oxyboryl carbanion and a 1,1-benzyldiboronate ester. Based on these results, we propose a mechanism for the CC bond generation involving a sequential radical borylation, "bora-Brook" rearrangement, B2pin2-mediated deoxygenation and a boron-Wittig process.
- Wang, Shun,Lokesh, Nanjundappa,Hioe, Johnny,Gschwind, Ruth M.,K?nig, Burkhard
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p. 4580 - 4587
(2019/05/14)
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- Pd/Cu-catalyzed facile approach to stilbenes: A novel diversity of TosMIC as an aryl source
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Pd/Cu-catalyzed Heck type cross-coupling reaction of p-toluenesulfonylmethyl isocyanide (TosMIC) with various styrenes to access stilbenes in DMSO solvent under mild conditions is developed. This efficient and simple approach employs TosMIC as an aryl sou
- Kadari, Lingaswamy,Palakodety, Radha Krishna
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supporting information
p. 1978 - 1981
(2019/07/03)
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- Nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H2
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A nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones to access various terminal and internal olefins with the liberation of hydrogen gas is reported.
- Landge, Vinod G.,Yadav, Vinita,Subaramanian, Murugan,Dangarh, Pragya,Balaraman, Ekambaram
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supporting information
p. 6130 - 6133
(2019/06/03)
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- Tetranuclear Palladium Complexes of Abnormal N-Heterocyclic Carbene Ligands and their Catalytic Activities in Mizoroki-Heck Coupling Reaction of Electron-Rich Aryl Chlorides
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Based on the ligand scaffold of an imidazolyl/benziimidazolyl moiety and a N-CH2C(=O)NHPh substituent, two series of ligand precursors with ortho hydroxy groups incorporated on the N-phenyl rings were prepared. The structural fine tuning of the ligand scaffold allowed the synthesis of tetranuclear palladium complexes with abnormal N-heterocyclic carbene (aNHC) ligands. For precursors with C2-methyl blocking groups, pyridine-assisted C?H bond activation led to the formation of mononuclear tridentate palladium aNHC complexes or tetranuclear complexes with tridentate CNO donors. Representative mononuclear and tetranuclearpalladium aNHC complexes were structurally characterized by X-ray diffraction studies, revealing very short Pd?C bond distances. The tetranuclear palladium aNHC complexes were very effective in catalyzing Mizoroki-Heck coupling reaction, and were capable of employing a range of aryl chlorides including deactivated substrates with low palladium loading of 0.2 mol%. (Figure presented.).
- Lee, Jhen-Yi,Su, Yong-Siang,Wang, Yu-Shan,Lee, Hon Man
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p. 4714 - 4726
(2019/09/03)
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- Synthesis and Catalytic Applications of [N,N]-Pyrrole Ligands for the Regioselective Synthesis of Styrene Derivatives
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We report the synthesis of two [N,N]-donor ligands (5 a–b) containing a 2-chalcogenazoline as the structural motif. These compounds were synthesized from a common intermediate Fischer type aminocarbene complex (3). The palladium-complexes of these [N,N]-donor ligands were successfully used as catalytic precursors in the Mizoroki-Heck coupling reaction between aryl halides and methyl acrylate, styrene and ethylene. For methyl acrylates, high yields with TOF values between 0.6 and 5.5×105 h?1 were obtained. In the case of ethylene, we reached high regioselectivities to obtain a diversity of styrene derivatives under soft pressure conditions, with good values of TON and TOF. (Figure presented.).
- Hochberger-Roa, Frank,Cortés-Mendoza, Salvador,Gallardo-Rosas, David,Toscano, Ruben A.,Ortega-Alfaro, M. Carmen,López-Cortés, José G.
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p. 4055 - 4064
(2019/07/31)
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- Porous organic polymer supported rhodium as a heterogeneous catalyst for hydroformylation of alkynes to α,β-unsaturated aldehydes
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A new porous organic polymer supported rhodium catalyst (Rh/POL-BINAPa&PPh3) has been developed for the hydroformylation of various alkynes to afford the corresponding α,β-unsaturated aldehydes with high chem- and stereoselectivity, excellent catalytic activity and good reusability (10 cycles). The heterogeneous catalyst exhibited more catalytic activity than the comparable homogeneous Rh/BINAPa/PPh3 system.
- Liang, Zuyu,Chen, Jianbin,Chen, Xin,Zhang, Kai,Lv, Jinhe,Zhao, Haowen,Zhang, Guoying,Xie, Congxia,Zong, Lingbo,Jia, Xiaofei
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p. 13721 - 13724
(2019/11/19)
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- Selenolate Anion as an Organocatalyst: Reactions and Mechanistic Studies
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A new organocatalyst, the selenolate anion [RSe]–, generated from bench-stable and commercially available diphenyl diselenide or from phenyl benzyl selenide (10 mol%) is introduced. Benchmarking is performed in the conversion of benzylic chlorides into trans-stilbenes selectively at room temperature. Mechanistic studies support the intermediacy of the selenolate anion and of 1,2-diphenylethyl phenyl selenide. (Figure presented.).
- Trofymchuk, Oleksandra S.,Zheng, Zhipeng,Kurogi, Takashi,Mindiola, Daniel J.,Walsh, Patrick J.
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p. 1685 - 1692
(2018/03/21)
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- Pd(OAc)2 immobilized on imine-functionalized microporous covalent triazine polymer as efficient heterogeneous catalyst for Mizoroki–Heck cross-coupling reaction
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A template consisting of Pd(OAc)2 immobilized on imine-functionalized microporous covalent triazine polymer network (Pd/TATAE) was synthesized and found to be an efficient and recyclable heterogeneous solid catalyst for Mizoroki–Heck C–C coupling of styrene with substituted aryl halides under mild reaction conditions and without addition of any ligand or additives. Furthermore, Pd/TATAE could be recycled for nine consecutive cycles with minor loss of catalytic activity. Finally, the Pd/TATAE catalyst showed good catalytic activity with excellent yield of 96?% and high turnover number of 3349.
- Sadhasivam, Velu,Mathappan, Mariyappan,Harikrishnan, Muniyasamy,Chithiraikumar, Chinnadurai,Murugesan, Sepperumal,Siva, Ayyanar
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p. 2853 - 2866
(2018/02/16)
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- Efficient Mizoroki–Heck coupling reactions using phosphine-modified Pd(II)–picolinate complex
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Efficient Mizoroki–Heck couplings were obtained using a very easily synthesizable palladium(II) complex of hemilabile N–O ligand (picolinate), with high turnover frequencies up to >10,000 h?1, in just 15 min, with high selectivity of >99% to the desired products. Wide applicability of the simple-looking palladium complex catalyst was established with differently functionalized substrates. Catalyst screening studies revealed intricate details of dependence of catalyst performance on different reaction parameters and conditions and arriving at the optimized facile methodology.
- Sharma, Sonam,Sarkar, Bibhas R.
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supporting information
p. 906 - 914
(2018/03/21)
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- Decarboxylative Arylation of α,β-Unsaturated Carboxylic Acids Using Aryl Triazenes by Copper/Ionic Liquid Combination in PEG-400
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A practical method for the construction of stilbene derivatives has been developed via catalytic cross-coupling of cinnamic acids with aryl triazenes. The methodology offers high stereoselectivity and is endowed with broad substrate scope, high yield, and significant functional group tolerance.
- Kumar, Saurabh,Kumar Pandey, Anand,Singh, Rahul,Nand Singh, Krishna
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supporting information
p. 5942 - 5946
(2018/11/10)
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- Direct Conversion of Alcohols into Alkenes by Dehydrogenative Coupling with Hydrazine/Hydrazone Catalyzed by Manganese
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We have developed unprecedented methods for the direct transformation of primary alcohols to alkenes in the presence of hydrazine, and for the synthesis of mixed alkenes by the reaction of alcohols with hydrazones. The reactions are catalyzed by a manganese pincer complex and proceed in absence of added base or hydrogen acceptors, liberating dihydrogen, dinitrogen, and water as the only byproducts. The proposed mechanism, based on preparation of proposed intermediates and control experiments, suggests that the transformation occurs through metal–ligand cooperative N?H activation of a hydrazone intermediate.
- Das, Uttam Kumar,Chakraborty, Subrata,Diskin-Posner, Yael,Milstein, David
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supporting information
p. 13444 - 13448
(2018/09/14)
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- Oxidative Dephosphorylation of Benzylic Phosphonates with Dioxygen Generating Symmetrical trans-Stilbenes
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Under a dioxygen atmosphere, benzylphosphonates and related phosphoryl compounds can readily produce the corresponding trans-stilbenes in high yields with high selectivity upon treatment with bases. Various functional groups were tolerable under the reaction conditions.
- Huang, Tianzeng,Chen, Tieqiao,Han, Li-Biao
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p. 2959 - 2965
(2018/03/09)
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- Method for preparing trans-diphenylethylene compound
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The invention relates to a preparation method of organic compounds and provides a method for preparing a trans-diphenylethylene compound. The method comprises adding a gem-dibromomethyl aromatic hydrocarbon compound, copper and polyamine into a reactor in the presence of a solvent, carrying out deoxidizing treatment, adding an oxygen-free water-free solvent into the reactor, carrying out a coupling reaction process to obtain C-C- double bonds, and carrying out separation and purification to obtain the trans-diphenylethylene compound. The method has mild synthesis conditions and has good reaction compatibility to different functional groups. The gem-dibromomethyl aromatic hydrocarbon compound as a raw material is easy to synthesize, may have different substituent groups and has a variable structure. The product obtained by coupling a raw material can be simply treated and has high purity. The asymmetric trans-diphenylethylene compound can be prepared from two different raw materials.
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Paragraph 0096; 0097; 0098; 0099; 0104; 0105; 0107
(2017/09/01)
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- Tandem Hydrosilylation/o-C-H Silylation of Arylalkynes Catalyzed by Ruthenium Bis(silyl) Aminophosphine Complexes
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An unprecedented reaction via consecutive trans-selective hydrosilylation and o-C-H silylation of arylalkynes with hydrosilanes was developed by use of ruthenium complex catalysts Ru{?°3(Si,O,Si)-xantsil}(CO)(PR3) (R = NC4H8 (1-Pyrr), NC5H10 (1-Pip); xantsil = (9,9-dimethylxanthene-4,5-diyl)bis(dimethylsilyl)). This reaction proceeded with gentle heating at 40-60 °C and afforded novel 2,α-bis-silylated (Z)-stilbene or (Z)-styrene derivatives 2 together with an equimolar amount of (E)-/(Z)-arylalkenes as byproducts. The selectivity of the formation of 2 reached a maximum by employing catalyst 1-Pyrr ligated by the less bulky triaminophosphine P(NC4H8)3 and hydrosilane HSiMe(OSiMe3)2 having moderately bulky and electron withdrawing substituents.
- Kitano, Takeo,Komuro, Takashi,Ono, Rikima,Tobita, Hiromi
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supporting information
p. 2710 - 2713
(2017/08/21)
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- Ligand effect on the rhodium porphyrin catalyzed hydrogenation of [2.2]paracyclophane with water: Key bimetallic hydrogenation
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Rhodium porphyrin catalyzed hydrogenation of the aliphatic carbon-carbon σ-bond of [2.2]paracyclophane with water has been examined with a variety of tetraarylporphyrins and axial ligands. Mechanistic investigations show that RhIII(ttp)H, which can be derived from the reaction of [RhII(ttp)]2 with water without a sacrificial reductant, plays an important role in promoting bimetallic reductive elimination to give the hydrogenation product.
- Tam, Chun Meng,To, Ching Tat,Chan, Kin Shing
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supporting information
p. 10057 - 10063
(2017/08/09)
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- E-Stilbene derivatives synthesized by stereoselective reductive coupling of benzylic gem-dibromide promoted by Cu/polyamine
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Stereoselective reductive coupling reaction of benzylic gem-dibromide promoted by Cu/polyamine produces E-stilbene derivatives with high yield under mild conditions. It provides a short pathway to synthesize symmetrical and asymmetrical E-stilbene derivatives using cheap reagents and alkenyl-free starting material together with easy workup.
- Cao, Hua,Wang, Qi
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p. 2703 - 2706
(2017/06/23)
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- Facile utilisation of aldehyde bisulfite adducts: Synthesis of (E)-1,2- diphenylethenes
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Background: A one-pot coupling reaction of aldehyde bisulfite adducts was developed for McMurry reaction using Zn-TiCl4 in 1,4-dioxane solvent medium. The treatment of sodium hydroxy(phenyl)methane sulfonate (2a) with TiCl4 in 1,4-dioxane favoured the deprotection of the bisulfite adduct 2a, and the in situ regeneration of benzaldehyde (1a) underwent reductive coupling to afford stilbene 3a in a relatively good yield, thus leading to an improved synthesis of a series of (E)-1,2- diphenylethenes 3. The present approach provides a new solution to the inherent instability of aldehydes and also provides a direct access to C'C bond formation for the synthesis of 1,2-diphenylethenes from aryl aldehyde bisulfite adducts. Methods: All reactions were performed at 70-80o and the synthesized compounds were characterized by IR, 1H NMR, 13C NMR, and mass spectrometric techniques. Results: The present approach provides a new solution to the instability of aldehydes and also provides a direct access to C'C bond formation for the synthesis of 1,2-diphenylethenes from aryl aldehyde bisulfite adducts. Conclusion: In the present work, we have reported an efficient method for the synthesis of 1,2- diphenylethene derivatives. Aldehydes are commonly used as the starting materials in the McMurry reaction, which affords the stilbene derivatives, the core skeleton of various valuable compounds. To increase the stability of the aldehydes, bisulfite adducts are usually employed, but the deprotection process causes loss of process efficiency. To address this issue, we developed a method based on the single-pot reaction of aromatic bisulfite adduct using TiCl4/Zn in 1,4-dioxane.
- Vinay Kumar,Jaganmohan,Sandeep Reddy,Mohanty, Sandeep,Kumar, Jaydeep,Rao, Venkateswara
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p. 109 - 114
(2017/04/03)
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- Alkyne Semihydrogenation with a Well-Defined Nonclassical Co-H2 Catalyst: A H2 Spin on Isomerization and E-Selectivity
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The reactivity of a CoI-H2 complex was extended toward the semihydrogenation of internal alkynes. Under ambient temperatures and moderate pressures of H2, a broad scope of alkynes were semihydrogenated using a CoI-N2 precatalyst, resulting in the formation of trans-alkene products. Furthermore, mechanistic studies using 1H, 2H, and para-hydrogen induced polarization (PHIP) transfer NMR spectroscopy revealed cis-hydrogenation of the alkyne occurs first. The Co-mediated alkene isomerization afforded the E-selective products from a broad group of alkynes with good yields and E/Z selectivity.
- Tokmic, Kenan,Fout, Alison R.
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supporting information
p. 13700 - 13705
(2016/10/31)
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- An unprecedented oxidative intermolecular homo coupling reaction between two sp3C–sp3C centers under metal-free condition
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An unprecedented formation of benzylic sp3C–sp3C coupled dibenzylic products has been illustrated. The reactions have been carried out in the presence of three oxidizing reagents, i.e., diacetoxy-iodobenzene (IBDA), N-fluorobenzenesulfonimide (NFSI), and pyridine (Py) using toluene derivatives.
- Sahoo, Santosh K.
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p. 3476 - 3480
(2016/07/15)
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- Mono- and multifold C-C coupling reactions catalyzed by a palladium complex encapsulated in MIL-Cr as a three dimensional nano reactor
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The organic palladium complex (trans-dichlorobis(4-iodoaniline-κN)palladium(ii)) was encapsulated into a porous metal-organic framework MIL-Cr (Pd complex@MIL-Cr) using ship-in-a-bottle strategy. The novel catalyst as a three dimensional nanoreactor was fully characterized using different techniques such as XRD, BET, XPS, SEM, EDX, TEM and ICP. The Pd complex@MIL-Cr is isostructural to the parent MIL-Cr framework, with a high surface area and pore volume of ca. 1418 m2 g-1 and 0.87 cm3 g-1, respectively. The nanoreactor was highly efficient in the catalytic conversion of aryl halides, showing extraordinarily higher activity than the homogeneous Pd counterparts. Surprisingly, high yields were achieved in Suzuki-Miyaura and Heck coupling reactions of chloroarenes bearing a wide range of substituents. Besides, this protocol could be extended to the cross-couplings of 2-bromo and 2,6-dibromopyridine with arylboronic acids in excellent yields at room temperature. The Pd complex@MIL-Cr was also used as an efficient and convenient catalyst for the preparation of a series of C3-symmetric molecules with benzene, pyridine or pyrimidine units as the central core. Moreover, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity. Investigation of the nature of the recovered catalyst showed that the catalyst is converted to Pd nanoparticles.
- Rezaei, Saghar,Landarani-Isfahani, Amir,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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p. 92463 - 92472
(2016/10/11)
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- Immobilized Pd on (S)-methyl histidinate-modified multi-walled carbon nanotubes: A powerful and recyclable catalyst for Mizoroki-Heck and Suzuki-Miyaura C-C cross-coupling reactions in green solvents and under mild conditions
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A stable and powerful heterogeneous palladium catalyst was synthesized using immobilized palladium on (S)-methyl histidinate bonded onto the surface of multi-walled carbon nanotubes. The catalyst was characterized using a combination of Fourier transform infrared and X-ray photoelectron spectroscopies, transmission electron microscopy, X-ray powder diffraction and inductively coupled plasma, thermogravimetric and elemental analyses. This new air- and moisture-stable phosphine-free palladium catalyst was found to be highly active and reusable in Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions in poly(ethylene glycol) and aqueous ethanol as green solvents using an extremely small amount of palladium under mild conditions.
- Hajipour, Abdol R.,Khorsandi, Zahra
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p. 256 - 261
(2016/05/02)
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- Fe-Catalyzed Cross-Coupling Reaction of Vinylic Ethers with Aryl Grignard Reagents
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Iron-catalyzed cross-coupling reaction of vinylic ethers with aryl Grignard reagents is described. The reaction proceeded at room temperature with catalytic amounts of an iron salt without the aid of costly ligands and additives. In this catalytic system, vinylic C?O bonds were preferentially cleaved over aromatic C?O bonds of aryl ethers or aryl sulfonates.
- Iwasaki, Takanori,Akimoto, Ryo,Kuniyasu, Hitoshi,Kambe, Nobuaki
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supporting information
p. 2834 - 2837
(2016/10/24)
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- Ligand-Free Heck Reactions of Aryl Iodides: Significant Acceleration of the Rate through Visible Light Irradiation at Ambient Temperature
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A mild Heck reaction of aryl iodides and olefins was realized by the cooperation of a palladium and a photoredox catalyst under the irradiation of visible light. This protocol works well to synthesize stilbenes with high Z/E ratios and (E)-cinnamates in the absence of ligands at ambient temperature. Control experiments revealed that palladium salt, visible light and photoredox catalyst were all crucial for the achievement of this cross-coupling under mild conditions. (Figure presented.).
- Zhang, Heng,Huang, Xueliang
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supporting information
p. 3736 - 3742
(2016/12/16)
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- Cobalt(II)-catalysed transfer hydrogenation of olefins
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Catalytic transfer hydrogenation of olefins by isopropanol is achieved using an earth-abundant metal cobalt(ii) complex based on a pincer-type PNP ligand. A range of olefins including aromatic and aliphatic alkenes as well as internal and cyclic alkenes have been transfer hydrogenated in good to excellent yields. The catalyst also showed good functional group and water tolerance to olefin transfer hydrogenation reactions.
- Zhang, Guoqi,Yin, Zhiwei,Tan, Jiawen
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p. 22419 - 22423
(2016/03/26)
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- Metal-catalyzed formal amidation of alkenes under CO-free condition
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An effective procedure for synthesis of amides from alkenes and [Formula presented] via Pd and Fe catalysts under mild conditions is described. A series of benzamides containing various functional groups can be obtained in reasonable yield and the possible reaction pathway is proposed in this Letter.
- Zhang, Yuanyuan,Ye, Wenjing,Leng, Xue,He, Ying,Zhang, Hui,Xiao, Xiao
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supporting information
p. 4203 - 4206
(2016/08/24)
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- A new role for sulfenate anions: Organocatalysis
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(Chemical Equation Presented) The sulfenate anion is introduced for the first time as a catalyst and was found to facilitate the conversion of benzyl halides to trans-stilbenes. CPME=Cyclopentyl methyl ether.
- Schwan, Adrian L.
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p. 226 - 227
(2015/03/03)
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- Tert-butyl phenyl sulfoxide: A traceless sulfenate anion precatalyst
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tert-Butyl phenyl sulfoxide is employed as a traceless precatalyst for the generation of sulfenate anions under basic conditions and has been used to catalyze the coupling of benzyl halides to trans-stilbenes. The advantage of this precatalyst over previous precatalysts is that the byproduct generated on catalyst formation is a gas, facilitating product isolation in high purity. Using this second generation catalyst, a variety of trans-stilbenes were generated in 39-98% isolated yield.
- Zhang, Mengnan,Jia, Tiezheng,Sagamanova, Irina K.,Pericás, Miquel A.,Walsh, Patrick J.
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supporting information
p. 1164 - 1167
(2015/03/14)
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- An alkene-promoted borane-catalyzed highly stereoselective hydrogenation of alkynes to give Z- And E-alkenes
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The stereoselective hydrogenation of alkynes to alkenes is an extremely useful transformation in synthetic chemistry. Despite numerous reports for the synthesis of Zalkenes, the hydrogenation of alkynes to give E-alkenes is still not well resolved. In particular, selective preparation of both Z- and E-alkenes by the same catalytic hydrogenation system using molecular H2 has rarely been reported. In this paper, a novel strategy of using simple alkenes as promoters for the HB(C6F5)2-catalyzed metal-free hydrogenation of alkynes was adopted. Significantly, both Z - and E-alkenes can be furnished by hydrogenation with molecular H2 in high yields with excellent stereoselectivities. Further experimental and theoretical mechanistic studies suggest that interactions between H and F atoms of the alkene promoter, borane intermediate, and H2 play an essential role in promoting the hydrogenolysis reaction.
- Liu, Yongbing,Hu, Lianrui,Chen, Hui,Du, Haifeng
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supporting information
p. 3495 - 3501
(2015/03/04)
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- An efficient trifunctional benzhydrazone ligated Pd(II) complex for Heck reaction of aryl bromides
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Synthesis of air and thermally stable trifunctional O, N, and O-terdentate benzhydrazone Pd(II) complex is reported and characterized by elemental analysis, spectral methods, and single crystal X-ray crystallographic technique. The new and reusable homogeneous catalyst has been effectively applied to the Mizoroki-Heck reaction of activated and deactivated aryl bromides with various olefins under mild reaction conditions in good to excellent yields up to 99%.
- Muthumari, Subramanian,Mohan, Nanjan,Ramesh, Rengan
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supporting information
p. 4170 - 4174
(2015/06/22)
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- Structural requirements for palladium catalyst transfer on a carbon-carbon double bond
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Intramolecular transfer of tBu3PPd(0) on a carbon-carbon double bond (C=C) was investigated by using Suzuki-Miyaura coupling reaction of dibromostilbenes with aryl boronic acid or boronic acid esters in the presence of various additi
- Nojima, Masataka,Ohta, Yoshihiro,Yokozawa, Tsutomu
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supporting information
p. 5682 - 5685
(2015/05/20)
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