- Scanning Electrochemical Microscopy. 33. Application to the Study of ECE/DISP Reactions
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The scanning electrochemical microscope (SECM) is used to measure the kinetics of ECE/DISP type reactions.The theory of the steady-state feedback response is developed in terms of numerical simulation.The theoretical curves show that the variation of the tip and substrate current with the tip-substrate separation can readily be used to differentiate between an ECE and a DISP1 pathway.The theoretical results suggest that rate constants up to 1.6E5 s-1 can be measured with tip sizes usually employed in SECM.The theory is validated using the experimental example of the reduction of anthracene in DMF in the presence of phenol.The reaction is shown to follow a DISP1 pathway, in agreement with previous studies.Good agreement is found between theory and experiment for all the phenol concentrations explored, and a rate constant of (4.4 +/- 0.4)E3 M-1 s-1 has been determined for the protonation of the anthracene radical anion by phenol.
- Demaille, Christophe,Unwin, Patrick R.,Bard, Allen J.
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Read Online
- Electron Transfer Catalysis of Arene Deco-ordination in the Cationic (η5-Cyclopentadienyl)(η6-arene)iron(II) Complexes
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Replacement of the arene group in 5-C5H5)(η6-C6H6-nMen)>+ (n = 4) by three P(OMe)3 ligands is carried out under mild conditions by reductive electron transfer catalysis in acetonitrile and gives the free a
- Darchen, Andre
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Read Online
- Tetra-anion of 9,9'-Bianthryl
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9,9'-Bianthryl is reduced with lithium to yield a stable tetra-anion which can be characterised by n.m.r. spectroscopy and chemical evidence.
- Huber, Walter,Muellen, Klaus
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Read Online
- A novel Birch reduction of aromatic compounds using aqueous titanium trichloride: Anions of trans-10b,10c-dimethyl-2,7,10b,10c-tetrahydropyrene
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The Birch reduction of 10b,10c-dimethyl-10b,10c-dihydropyrene 1 and anthracene could be predicted on the basis of their reduction potentials and achieved readily with aqueous titanium trichloride in near quantitative yields. Controlled reduction of a nitro group could be achieved under these conditions with the aromatic hydrocarbon remaining intact. The anion derived from the hexane obtained from reduction of 1 provided synthetic routes to derivatives of 1 inaccessible from direct substitution reactions of 1. Oxidative dimerization of the anion led to the formation of a series of interesting products.
- Jiang, Jianping,Lai, Yee-Hing
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Read Online
- Dimerization of cycloproparenes by silver ion
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Cycloproparenes react with silver ion chloroform to yield dimers which can be aromatized by dichlorodicyanoquinone in benzene to give the corresponding acene.
- Billups,McCord, Dianne J.,Maughon, Bob R.
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Read Online
- Metal-free hydrogenation catalysis of polycyclic aromatic hydrocarbons
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The frustrated Lewis pair, B(C6F5) 3/Ph2PC6F5, acts as an efficient catalyst for the hydrogenation of the polycyclic hydrocarbons including anthracene derivatives, tetracene and tetraphene, at 80 °C and 100 atm H2 pressure via a mechanism involving protonation of polyaromatic species followed by hydride transfer. The Royal Society of Chemistry.
- Segawa, Yasutomo,Stephan, Douglas W.
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Read Online
- Method for reducing carbonyl reduction to methylene under illumination
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The invention belongs to the technical field of organic chemical synthesis. The method comprises the following steps: (1) mixing the carbonyl compound and the amine compound in a solvent, reacting 3 - 6 under the illumination of 380 - 456 nm, the reaction system is low in toxicity, high in atom utilization rate 12 - 24h. and production efficiency, safe and controllable in reaction process and capable of simplifying the operation in the preparation and production process. At the same time, the residue toxicity of the reaction is minimized, the pollution caused by the production process to the environment is reduced, and the steps and operations of removing residues after the reaction are simplified. In addition, the reactant feedstock is readily available. The reactant does not need additional modification before the reaction, can be directly used for preparing production, simplifies the operation steps, and shortens the reaction route. The production cost is obviously reduced.
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Paragraph 0033-0038; 0089-0098
(2021/09/29)
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- Noble metal nanoparticles stabilized by hyper-cross-linked polystyrene as effective catalysts in hydrogenation of arenes
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This work is addressing the arenes’ hydrogenation—the processes of high importance for petrochemical, chemical and pharmaceutical industries. Noble metal (Pd, Pt, Ru) nanoparticles (NPs) stabilized in hyper-cross-linked polystyrene (HPS) were shown to be active and selective catalysts in hydrogenation of a wide range of arenes (monocyclic, condensed, substituted, etc.) in a batch mode. HPS effectively stabilized metal NPs during hydrogenation in different medium (water, organic solvents) and allowed multiple catalyst reuses.
- Bakhvalova, Elena S.,Bykov, Alexey V.,Demidenko, Galina N.,Kiwi-Minsker, Lioubov,Mikheev, Alexey V.,Nikoshvili, Linda Z.,Pinyukova, Arina O.,Sulman, Mikhail G.
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- Visible light enables catalytic formation of weak chemical bonds with molecular hydrogen
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The synthesis of weak chemical bonds at or near thermodynamic potential is a fundamental challenge in chemistry, with applications ranging from catalysis to biology to energy science. Proton-coupled electron transfer using molecular hydrogen is an attractive strategy for synthesizing weak element–hydrogen bonds, but the intrinsic thermodynamics presents a challenge for reactivity. Here we describe the direct photocatalytic synthesis of extremely weak element–hydrogen bonds of metal amido and metal imido complexes, as well as organic compounds with bond dissociation free energies as low as 31 kcal mol?1. Key to this approach is the bifunctional behaviour of the chromophoric iridium hydride photocatalyst. Activation of molecular hydrogen occurs in the ground state and the resulting iridium hydride harvests visible light to enable spontaneous formation of weak chemical bonds near thermodynamic potential with no by-products. Photophysical and mechanistic studies corroborate radical-based reaction pathways and highlight the uniqueness of this photodriven approach in promoting new catalytic chemistry. [Figure not available: see fulltext.].
- Park, Yoonsu,Kim, Sangmin,Tian, Lei,Zhong, Hongyu,Scholes, Gregory D.,Chirik, Paul J.
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p. 969 - 976
(2021/07/25)
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- Catalyzed transfer hydrogenation by 2-propanol for highly selective PAHs reduction
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Catalytic hydrogenation of mono-, di- and trinuclear aromatic compounds has been studied under hydrogen transfer conditions at 150 °C and 82 °C in 2-PrOH as a hydrogen donor and with Raney nickel as a catalyst. In contrast to conjugated or condensed aromatic rings, isolated ones demonstrated low reactivity in transfer hydrogenation (TH) that can be used to increase the hydrogenation selectivity of the reaction. So, naphthalene and biphenyl are partially hydrogenated into tetralin and cyclohexylbenzene, respectively, with excellent conversion (≥ 96 %) and selectivity (≥ 98 %) for 5–6 h at 82 °C. Increasing the reaction temperature to 150 °C results expectedly in the hydrogenation of second aromatic ring, which occurs slowly enough. Only 8 % of decaline and 42 % of dicyclohexyl, correspondingly, were obtained after 5 h at 150 °C. At the same time, TH of trinuclear anthracene and phenanthrene at 150 °C resulted in the formation of deeper hydrogenated octahydro-anthracenes and -phenanthrenes, respectively.
- Philippov,Chibiryaev,Martyanov
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- Sodium-Promoted Borylation of Polycyclic Aromatic Hydrocarbons
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Sodium dispersion promotes the reductive borylation of polycyclic aromatic hydrocarbons (PAHs) with MeOBpin. Anthracenes and phenanthrenes are converted to the corresponding dearomatized diborylated products. The reductive diborylation of naphthalene-based small π-systems yields similar yet unstable products that are oxidized into formal C-H borylation products with unique regioselectivity. Pyrene is converted to 1-borylpyrene without the addition of an oxidant. The latter two reactions represent a new route to useful borylated PAHs that rivals C-X borylation and catalytic C-H borylation.
- Fukazawa, Mizuki,Takahashi, Fumiya,Yorimitsu, Hideki
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supporting information
p. 4613 - 4617
(2021/06/28)
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- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
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A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
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supporting information
p. 2095 - 2103
(2021/03/26)
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- Conversion of Aryl Aldehydes to Benzyl Iodides and Diarylmethanes by H3PO3/I2
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For the first time, H3PO3 was used as both the reducing reagent and the promotor in the reductive benzylation reactions with aryl aldehydes. By using a H3PO3/I2 combination, various aromatic aldehydes underwent iodination reactions and Friedel-Crafts type reactions with arenes via benzyl iodide intermediates, readily producing benzyl iodides and diarylmethanes in good yields. Intramolecular cyclization reactions also took place, giving the corresponding cyclic compounds. This new strategy features easy-handling, low-cost, and metal-free conditions.
- Lv, Fang,Xiao, Jing,Xiang, Junchun,Guo, Fengzhe,Tang, Zi-Long,Han, Li-Biao
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p. 3081 - 3088
(2021/02/01)
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- Hydrogenation reaction method
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The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0229-0232
(2020/05/14)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- In situelectrosynthesis of anthraquinone electrolytes in aqueous flow batteries
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We demonstrate the electrochemical oxidation of an anthracene derivative to a redox-active anthraquinone at room temperature in a flow cell without the use of hazardous oxidants or noble metal catalysts. The anthraquinone, generatedin situ, was used as the active species in a flow battery electrolyte without further modification or purification. This potentially scalable, safe, green, and economical electrosynthetic method is also applied to another anthracene-based derivative and may be extended to other redox-active aromatics.
- Aziz, Michael J.,Fell, Eric M.,Gordon, Roy G.,Jin, Shijian,Jing, Yan,Kerr, Emily F.,Pollack, Daniel A.,Wong, Andrew A.,Wu, Min
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supporting information
p. 6084 - 6092
(2020/10/14)
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- Trishomoaromatic (B3N3Ph6) Dianion: Characterization and Two-Electron Reduction
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Benzene, a common aromatic compound, can be converted into an unstable antiaromatic 8π-electron intermediate through two-electron reduction. However, as an isoelectronic equivalent of benzene, borazine (B3N3Ph6), having weak aromaticity, undergoes a totally different two-electron reduction to afford (B3N3R6)2? homoaromatic compounds. Reported here is the synthesis of homoaromatic (B3N3Ph6)2? by the reduction of B3N3Ph6 with either potassium or rubidium in the presence of 18-crown-6 ether. Theoretical investigations illustrate that two electrons delocalize over the three boron atoms in (B3N3Ph6)2?, which is formed by the geometric and orbital reorganization and exhibits (π,σ)-mixed homoaromaticity. Moreover, (B3N3Ph6)2? can act as a robust 2e reductant for unsaturated compounds, such as anthracene, chalcone, and tanshinones. This 2e reduction is of high efficiency and selectivity, proceeds under mild reaction conditions, and can regenerate neutral borazine.
- Li, Nan,Li, Tianyu,Wu, Botao,Xi, Zhenfeng,Yu, Chao,Zhang, Wen-Xiong
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supporting information
p. 8868 - 8872
(2020/04/22)
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- Highly Active Superbulky Alkaline Earth Metal Amide Catalysts for Hydrogenation of Challenging Alkenes and Aromatic Rings
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Two series of bulky alkaline earth (Ae) metal amide complexes have been prepared: Ae[N(TRIP)2]2 (1-Ae) and Ae[N(TRIP)(DIPP)]2 (2-Ae) (Ae=Mg, Ca, Sr, Ba; TRIP=SiiPr3, DIPP=2,6-diisopropylphenyl). While monomeric 1-Ca was already known, the new complexes have been structurally characterized. Monomers 1-Ae are highly linear while the monomers 2-Ae are slightly bent. The bulkier amide complexes 1-Ae are by far the most active catalysts in alkene hydrogenation with activities increasing from Mg to Ba. Catalyst 1-Ba can reduce internal alkenes like cyclohexene or 3-hexene and highly challenging substrates like 1-Me-cyclohexene or tetraphenylethylene. It is also active in arene hydrogenation reducing anthracene and naphthalene (even when substituted with an alkyl) as well as biphenyl. Benzene could be reduced to cyclohexane but full conversion was not reached. The first step in catalytic hydrogenation is formation of an (amide)AeH species, which can form larger aggregates. Increasing the bulk of the amide ligand decreases aggregate size but it is unclear what the true catalyst(s) is (are). DFT calculations suggest that amide bulk also has a noticeable influence on the thermodynamics for formation of the (amide)AeH species. Complex 1-Ba is currently the most powerful Ae metal hydrogenation catalyst. Due to tremendously increased activities in comparison to those of previously reported catalysts, the substrate scope in hydrogenation catalysis could be extended to challenging multi-substituted unactivated alkenes and even to arenes among which benzene.
- Eyselein, Jonathan,F?rber, Christian,Grams, Samuel,Harder, Sjoerd,Knüpfer, Christian,Langer, Jens,Martin, Johannes,Thum, Katharina,Wiesinger, Michael
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supporting information
p. 9102 - 9112
(2020/03/30)
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- Exploiting the radical reactivity of diazaphosphinanes in hydrodehalogenations and cascade cyclizations
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The remarkable reducibility of diazaphosphinanes has been extensively applied in various hydrogenations, based on and yet limited by their well-known hydridic reactivity. Here we exploited their unprecedented radical reactivity to implement hydrodehalogenations and cascade cyclizations originally inaccessible by hydride transfer. These reactions feature a broad substrate scope, high efficiency and simplicity of manipulation. Mechanistic studies suggested a radical chain process in which a phosphinyl radical is generated in a catalytic cycle via hydrogen-atom transfer from diazaphosphinanes. The radical reactivity of diazaphosphinanes disclosed here differs from their well-established hydridic reactivity, and hence, opens a new avenue for diazaphosphinane applications in organic syntheses.
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing
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p. 4786 - 4790
(2020/06/18)
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- General and Chemoselective Copper Oxide Catalysts for Hydrogenation Reactions
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Copper oxide catalysts have been prepared by pyrolysis of copper acetate on aluminum oxide. The material resulting from pyrolysis at 800 °C allows for catalytic hydrogenations at low temperature of a variety of unsaturated compounds such as quinolines, alkynes, ketones, imines, and polycyclic aromatic hydrocarbons as well as nitroarenes with good activity and selectivity.
- Li, Wu,Cui, Xinjiang,Junge, Kathrin,Surkus, Annette-Enrica,Kreyenschulte, Carsten,Bartling, Stephan,Beller, Matthias
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p. 4302 - 4307
(2019/05/08)
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- Birch-Type Photoreduction of Arenes and Heteroarenes by Sensitized Electron Transfer
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The direct reduction of arenes and heteroarenes by visible-light irradiation remains challenging, as the energy of a single photon is not sufficient for breaking aromatic stabilization. Shown herein is that the energy accumulation of two visible-light photons allows the dearomatization of arenes and heteroarenes. Mechanistic investigations confirm that the combination of energy-transfer and electron-transfer processes generates an arene radical anion, which is subsequently trapped by hydrogen-atom transfer and finally protonated to form the dearomatized product. The photoreduction converts planar aromatic feedstock compounds into molecular skeletons that are of use in organic synthesis.
- Chatterjee, Anamitra,K?nig, Burkhard
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supporting information
p. 14289 - 14294
(2019/08/30)
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- Dual Role of Doubly Reduced Arylboranes as Dihydrogen- and Hydride-Transfer Catalysts
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Doubly reduced 9,10-dihydro-9,10-diboraanthracenes (DBAs) are introduced as catalysts for hydrogenation as well as hydride-transfer reactions. The required alkali metal salts M2[DBA] are readily accessible from the respective neutral DBAs and Li metal, Na metal, or KC8. In the first step, the ambiphilic M2[DBA] activate H2 in a concerted, metal-like fashion. The rates of H2 activation strongly depend on the B-bonded substituents and the counter cations. Smaller substituents (e.g., H, Me) are superior to bulkier groups (e.g., Et, pTol), and a Mes substituent is even prohibitively large. Li+ ions, which form persistent contact ion pairs with [DBA]2-, slow the H2-addition rate to a higher extent than more weakly coordinating Na+/K+ ions. For the hydrogenation of unsaturated compounds, we identified Li2[4] (Me substituents at boron) as the best performing catalyst; its substrate scope encompasses Ph(H)CNtBu, Ph2CCH2, and anthracene. The conversion of E-Cl to E-H bonds (E = C, Si, Ge, P) was best achieved by using Na2[4]. The latter protocol provides facile access also to Me2Si(H)Cl, a most important silicone building block. Whereas the H2-transfer reaction regenerates the dianion [4]2- and is thus immediately catalytic, the H--transfer process releases the neutral 4, which has to be recharged by Na metal before it can enter the cycle again. To avoid Wurtz-type coupling of the substrate, the reduction of 4 must be performed in the absence of the element halide, which demands an alternating process management (similar to the industrial anthraquinone process).
- Von Grotthuss, Esther,Prey, Sven E.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
(2019/04/17)
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- Dual Role of Doubly Reduced Arylboranes as Dihydrogen- and Hydride-Transfer Catalysts
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Doubly reduced 9,10-dihydro-9,10-diboraanthracenes (DBAs) are introduced as catalysts for hydrogenation as well as hydride-transfer reactions. The required alkali metal salts M2[DBA] are readily accessible from the respective neutral DBAs and Li metal, Na metal, or KC8. In the first step, the ambiphilic M2[DBA] activate H2 in a concerted, metal-like fashion. The rates of H2 activation strongly depend on the B-bonded substituents and the counter cations. Smaller substituents (e.g., H, Me) are superior to bulkier groups (e.g., Et, pTol), and a Mes substituent is even prohibitively large. Li+ ions, which form persistent contact ion pairs with [DBA]2-, slow the H2-addition rate to a higher extent than more weakly coordinating Na+/K+ ions. For the hydrogenation of unsaturated compounds, we identified Li2[4] (Me substituents at boron) as the best performing catalyst; its substrate scope encompasses Ph(H)C=NtBu, Ph2C=CH2, and anthracene. The conversion of E-Cl to E-H bonds (E = C, Si, Ge, P) was best achieved by using Na2[4]. The latter protocol provides facile access also to Me2Si(H)Cl, a most important silicone building block. Whereas the H2-transfer reaction regenerates the dianion [4]2- and is thus immediately catalytic, the H--transfer process releases the neutral 4, which has to be recharged by Na metal before it can enter the cycle again. To avoid Wurtz-type coupling of the substrate, the reduction of 4 must be performed in the absence of the element halide, which demands an alternating process management (similar to the industrial anthraquinone process).
- Von Grotthuss, Esther,Prey, Sven E.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
p. 6082 - 6091
(2019/04/17)
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- Task-Dependent Coordination Levels of SmI2
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Ligation plays a multifaceted role in the chemistry of SmI2. Depending on the ligand, two of its major effects are increasing the reduction potential of SmI2, and in the case of a ligand, which is also a proton donor, it may also enhance the reaction by protonation of the radical anion generated in the preceding step. It turns out that the number of ligand molecules that are needed to maximize the reduction potential of SmI2 is significantly smaller than the number of ligand molecules needed for a maximal enhancement of the protonation rate. In addition to the economical use of the ligand, this information can also be utilized as a diagnostic tool for the reaction mechanism in differentiating between single and multistep processes. The possible pitfalls in applying this diagnostic tool to PCET and cyclization reactions are discussed.
- Maity, Sandeepan,Nimkar, Amey,Hoz, Shmaryahu
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supporting information
p. 1994 - 1998
(2019/05/16)
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- ELECTROCHEMICAL REDUCTIVE CARBOXYLATION OF UNSATURATED ORGANIC SUBSTRATES IN IONICALLY CONDUCTIVE MEDIUMS
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The disclosure relates to methods for electrochemical reductive carboxylation of an unsaturated organic substrate to form a dicarboxylic organic product. The unsaturated organic substrate is electrochemically reduced with a carbon dioxide reactant in an ionically conductive, water-immiscible reactant medium to form the dicarboxylic organic product. The dicarboxylic organic product is recovered in an aqueous product medium. Example dicarboxylic organic products include phthalic acid, naphthalenedicarboxylic acid, furan-2,5-dicarboxylic acid, thiophene-2,5-dicarboxylic acid, pyrrole-2,5-dicarboxylic acid, adipic acid, suberic acid, sebacic acid, and 1,12-dodecanedioic acid.
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Paragraph 0118
(2019/02/13)
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- Hydrogenation of naphthalene and anthracene on Pt/C catalysts
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Hydrogenation of naphthalene and anthracene deposited on Sibunit and active carbon was studied. The reactions were carried out at a temperature of 280 °C and a pressure of 90 atm. The directions for the complete hydrogenation of the investigated substrates were studied. Correlations between the structures of naphthalene and anthracene and their activity in hydrogen absorption are presented. The hydrogenation rates decrease as the substrate is saturated with hydrogen.
- Kalenchuk,Koklin,Bogdan,Kustov
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p. 1406 - 1411
(2018/10/31)
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- Transition metal-free regioselective access to 9,10-dihydroanthracenes via the reaction of anthracenes with elemental phosphorus in the KOH/DMSO system
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Anthracene and its 9- or 9,10-substituted (Me, Ph, Cl, Br) derivatives react with red phosphorus (Pn) in the KOH/DMSO superbase system at 85–120 °C to afford 9,10-dihydroanthracenes in good to excellent yields, thus providing simple and clean access to these extensively used dihydroaromatics.
- Kuimov, Vladimir A.,Gusarova, Nina K.,Malysheva, Svetlana F.,Trofimov, Boris A.
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supporting information
p. 4533 - 4536
(2018/11/27)
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- Strontium-mediated selective protonation of unsaturated linkage of aromatic hydrocarbons and these derivatives
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The selective protonation of aromatic hydrocarbons with at least two or more aromatic rings and aromatic compounds bearing unsaturated linkages can be achieved by metallic strontium metal with ammonium chloride and iodine, or ammonium iodide in tetrahydrofuran. The reaction system is ammonia-free in room temperature and the reaction proceeds high selectivity in moderate to good yields.
- Ohmura, Satoshi D.,Ueno, Masaharu,Miyoshi, Norikazu
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supporting information
p. 2268 - 2271
(2018/05/16)
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- A Practical and Chemoselective Ammonia-Free Birch Reduction
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A novel protocol for a significantly improved, practical, and chemoselective ammonia-free Birch reduction mediated by bench-stable sodium dispersions and recoverable 15-crown-5 ether is reported. A broad range of aromatic and heteroaromatic compounds is reduced with excellent yields.
- Lei, Peng,Ding, Yuxuan,Zhang, Xiaohe,Adijiang, Adila,Li, Hengzhao,Ling, Yun,An, Jie
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supporting information
p. 3439 - 3442
(2018/06/26)
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- Birch Reduction of Aromatic Compounds by Inorganic Electride [Ca2N]+?e- in an Alcoholic Solvent: An Analogue of Solvated Electrons
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Birch reduction of aromatic systems by solvated electrons in alkali metal-ammonia solutions is widely recognized as a key reaction that functionalizes highly stable π-conjugated organic systems. In spite of recent advances in Birch reduction with regard to reducing agent and reaction conditions, there remains an ongoing challenge to develop a simple and efficient Birch reaction under mild conditions. Here, we demonstrate that the inorganic electride [Ca2N]+?e- promotes the Birch reduction of polycyclic aromatic hydrocarbons (PAHs) and naphthalene under alcoholic solvent in the vicinity of room temperature as a solid-type analogy to solvated electrons in alkali metal ammonia solutions. The anionic electrons from electride [Ca2N]+?e- are transferred to PAHs and naphthalene via alcoholysis in a polar cosolvent medium. It is noteworthy that a high conversion yield to the hydrogenated products is ascribed to the extremely high electron transfer efficiency of 98%. This simple protocol utilizing an inorganic electride offers a direct and practical strategy for the reduction of aromatic compounds and provides an outstanding reducing agent for synthetic chemistry.
- Yoo, Byung Il,Kim, Ye Ji,You, Youngmin,Yang, Jung Woon,Kim, Sung Wng
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supporting information
p. 13847 - 13853
(2018/11/23)
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- Novel electronic salt system and method for reducing unsaturated hydrocarbon compound
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The invention discloses an electronic salt system and a method for reducing unsaturated hydrocarbon compounds by using the electronic salt system, belongs to the field of organic synthesis, and solvesthe problems such as complicated operation, harsh conditions, easy generation of complex over-reduction products of methods for reducing the unsaturated hydrocarbon compounds in the prior art. An electron salt may be synthesized by an alkali metal reagent, an ether and an alcohol, the ether can be a crown ether or a cryptand; and the method adopts the electronic salt system, the unsaturated hydrocarbon compounds is reduced by the electronic salt system in an organic solvent. The method for reducing the unsaturated hydrocarbon compounds is used for reducing the unsaturated hydrocarbon compounds.
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Paragraph 0088-0092
(2018/09/08)
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- Conjugate Addition of Perfluoroarenes to α,β-Unsaturated Carbonyls Enabled by an Alkoxide-Hydrosilane System: Implication of a Radical Pathway
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Conjugate addition of organometallic reagents to α,β-unsaturated carbonyls is a key strategy for the construction of carbon-carbon bond in organic synthesis. Although direct C-H addition to unsaturated bonds via transition metal catalysis is explored in recent years, electron-deficient arenes that do not bear directing groups continue to be challenging. Herein we disclose the first example of a conjugate addition of perfluoroarenes to α,β-unsaturated carbonyls enabled by an alkoxide-hydrosilane system. The reaction is convenient to carry out at room temperature over a broad range of substrates and reactants to furnish synthetically versatile products in high to excellent yields. Mechanistic experiments in combination with computational studies suggest that a radical pathway is most likely operative in this transformation. The hypervalent silicate and silanide species, which are relevant to the proposed mechanism, were observed experimentally by NMR and single crystal X-ray diffraction analyses.
- Xie, Weilong,Park, Sung-Woo,Jung, Hoimin,Kim, Dongwook,Baik, Mu-Hyun,Chang, Sukbok
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supporting information
p. 9659 - 9668
(2018/07/21)
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- Experimental and Theoretical Studies on the Implications of Halide-Dependent Aqueous Solvation of Sm(II)
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The addition of water to samarium(II) has been demonstrated to have a significant impact on the reduction of organic substrates, with the majority of research dedicated to the most widely used reagent, samarium diiodide (SmI2). The work presented herein focuses on the reducing capabilities of samarium dibromide (SmBr2) and demonstrates how the modest change in halide ligand results in observable mechanistic differences between the SmBr2-water and the SmI2-water systems that have considerable implications in terms of reactivity between the two reagents. Quantum chemical results from Born-Oppenheimer molecular dynamics simulations show significant differences between SmI2-water and SmBr2-water, with the latter displaying less dissociation of the halide, which results in a lower coordination number for water. Experimental results are consistent with computational results and demonstrate that the coordination sphere of SmBr2 is saturated at lower concentrations of water. In addition, coordination-induced bond-weakening of the O-H bond is demonstrably different for water bound to SmBr2, leading to an estimated O-H bond-weakening of at least 83 kcal/mol, nearly 10 kcal/mol larger than the bond-weakening observed in SmI2-H2O. Experimental results also demonstrate that the use of alcohols in place of water with SmBr2 leads to substrate reduction, albeit several orders of magnitude slower than for SmBr2-water. The difference in rates resulting from the change in proton donor is attributed to a rate-limiting proton-coupled electron transfer in SmBr2-water and a sequential electron transfer then proton transfer in SmBr2-alcohol systems, where electron transfer is rate-limiting.
- Ramírez-Solís, Alejandro,Bartulovich, Caroline O.,Chciuk, Tesia V.,Hernández-Cobos, Jorge,Saint-Martin, Humberto,Maron, Laurent,Anderson, William R.,Li, Anna M.,Flowers, Robert A.
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supporting information
p. 16731 - 16739
(2018/12/11)
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- Hydrogenation of Anthracene and Dehydrogenation of Perhydroanthracene on Pt/C Catalysts
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The hydrogenation of anthracene on a heterogeneous catalyst containing 3 wt % Pt/C (Aldrich) at 215, 245, and 280°C and the pressures of 40 and 90 atm is studied. The hydrogenation of anthracene to a completely hydrogenated product is considered in detail
- Kalenchuk,Koklin,Bogdan,Lunin
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p. 663 - 668
(2018/04/12)
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- Secondary amides as hydrogen atom transfer promoters for reactions of samarium diiodide
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Two secondary amides (N-methylacetamide and 2-pyrrolidinone) were used as additives with SmI2 in THF to estimate the extent of N-H bond weakening upon coordination. Mechanistic and synthetic studies demonstrate significant bond-weakening, providing a reagent system capable of reducing a range of substrates through formal hydrogen atom transfer.
- Chciuk, Tesia V.,Li, Anna M.,Vazquez-Lopez, Andres,Anderson, William R.,Flowers, Robert A.
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supporting information
p. 290 - 293
(2017/11/27)
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- Electron-Transfer and Hydride-Transfer Pathways in the Stoltz–Grubbs Reducing System (KOtBu/Et3SiH)
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Recent studies by Stoltz, Grubbs et al. have shown that triethylsilane and potassium tert-butoxide react to form a highly attractive and versatile system that shows (reversible) silylation of arenes and heteroarenes as well as reductive cleavage of C?O bonds in aryl ethers and C?S bonds in aryl thioethers. Their extensive mechanistic studies indicate a complex network of reactions with a number of possible intermediates and mechanisms, but their reactions likely feature silyl radicals undergoing addition reactions and SH2 reactions. This paper focuses on the same system, but through computational and experimental studies, reports complementary facets of its chemistry based on a) single-electron transfer (SET), and b) hydride delivery reactions to arenes.
- Smith, Andrew J.,Young, Allan,Rohrbach, Simon,O'Connor, Erin F.,Allison, Mark,Wang, Hong-Shuang,Poole, Darren L.,Tuttle, Tell,Murphy, John A.
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supporting information
p. 13747 - 13751
(2017/10/12)
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- Designing MoS2 nanocatalysts with increased exposure of active edge sites for anthracene hydrogenation reaction
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Designing MoS2 nanocatalysts rich with active edge sites by engineering of the nanostructures is an effective strategy to enhance their catalytic activity. A series of MoS2 nanoflowers with self-assembled nanosheets was successfully synthesized by engineering of nanostructures. The compositions and structures of MoS2 nanoflowers were characterized by elemental analysis, XPS, TG, XRD, Raman, SEM, and HRTEM. The growth mechanism for MoS2 samples was proposed. MoS2 nanoflowers with a short slab of 5-10 nm, 3-5 stacking layers and expanded basal spacing of 0.98 nm were synthesized via a one-pot solvothermal synthesis method using high boiling point and viscosity ethylene glycol as solvent, maximizing the exposure of active edge sites. In the catalytic anthracene hydrogenation reaction in a slurry-phase reactor, the hydrogenation percentage and selectivity to deep hydrogenation products of the optimized MoS2 nanoflowers are respectively 3.2 times and 31.2 times as high as those of commercial MoS2. The structure-activity relationship of MoS2 catalysts suggests that the engineering of nanostructures to increase the exposure of active edge sites can dramatically improve the catalytic hydrogenation performance of MoS2 catalysts. This study provides the theoretical instructions for designing MoS2 catalysts with improved activity. The increased understanding and research on MoS2 catalysts will drive the industrialization of heavy oil/residue conversion into clean fuels.
- Jiang, Yuxia,Wang, Donge,Li, Jiahe,Li, Min,Pan, Zhendong,Ma, Huaijun,Lv, Guang,Qu, Wei,Wang, Lin,Tian, Zhijian
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p. 2998 - 3007
(2017/08/01)
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- High-Affinity Proton Donors Promote Proton-Coupled Electron Transfer by Samarium Diiodide
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The relationship between proton-donor affinity for SmII ions and the reduction of two substrates (anthracene and benzyl chloride) was examined. A combination of spectroscopic, thermochemical, and kinetic studies show that only those proton donors that coordinate or chelate strongly to SmII promote anthracene reduction through a PCET process. These studies demonstrate that the combination of SmII ions and water does not provide a unique reagent system for formal hydrogen atom transfer to substrates.
- Chciuk, Tesia V.,Anderson, William R.,Flowers, Robert A.
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supporting information
p. 6033 - 6036
(2016/05/19)
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- Surface-exposed Pd nanoparticles supported over nanoporous carbon hollow tubes as an efficient heterogeneous catalyst for the C[sbnd]C bond formation and hydrogenation reactions
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Designing uniformly dispersed Pd nanoparticles over nanoporous carbon supports is very demanding in the context of heterogeneous catalysis. However in most of the cases cluster/agglomerated Pd particles are formed over carbon matrixes, which lack sufficient stability and formation of a sustainable passive layer that can prevent the direct contact between the active metal sites with the reactants. Herein we report the in-situ preparation of surface-exposed Pd nanoparticle over N-doped carbon hollow tubes i.e. Pd@CHT, which showed high catalytic activity compared with agglomerated Pd on carbon. The simplicity in the preparation of Pd@CHT via one step direct carbonization of hypercrosslinked polymer tubes followed by reduction in the presence of NaBH4 can offer huge potential in liquid phase heterogeneous catalysis. High dispersibility of the catalyst in the reaction medium, good stability and reusability of Pd@CHT is observed for the Sonogashira, cyanation and hydrogenation reactions for the synthesis of a wide range of value added fine chemicals, suggesting its future potential in heterogeneous catalysis.
- Modak, Arindam,Bhaumik, Asim
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p. 147 - 156
(2016/10/30)
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- Hydrogenation of Condensed Aromatic Compounds over Mesoporous Bifunctional Catalysts Following a Diels-Alder Adduct Pathway
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Pt(0.5 wt %)-Al-SBA-15 and Pt(0.5 wt %)-Al-MCM-41 bifunctional catalysts were prepared by wet impregnation and investigated in the hydrogenation of anthracene and the hydrogenolysis/hydrogenation of a series of synthesized Diels-Alder adducts with anthracene and anthracene derivatives. The mesoporous texture of the investigated catalysts allowed the hydrogenation of these substrates to a large extent. In direct correlation with the size of the Pt particles, Pt-Al-SBA-15 exhibited a higher activity. Both catalysts exhibited a strong Lewis acidity associated with the presence of the Al extra-framework species. The acidity of these catalysts afforded the esterification of the reaction byproduct, that is, succinic anhydride, with methanol or ethanol, and the hydrocracking/decyclization of one hydrogenated ring to lead to 1,2,3,4-tetrahydronaphthalene derivatives. A good correlation with the calculated values of the reaction Gibbs free energy has been evidenced.
- Huyen, Pham Thanh,Krivec, Marko,Ko?evar, Marijan,Bucur, Ioana C.,Rizescu, Cristina,Parvulescu, Vasile I.
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p. 1146 - 1156
(2016/04/05)
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- Transformation of Trifluorotoluenes Triggered by Titanium(IV) Chloride-Catalyzed Hydrodefluorination using Hydrosilanes
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The titanium tetrachloride-catalyzed hydrodefluorination reaction of trifluorotoluene derivatives was developed using triethylsilane as the reducing agent. The reaction produced various toluene derivatives with high chemoselectivities by means of readily accessible reagents. This hydrodefluorination process was extended to the intramolecular Friedel-Crafts benzylation reaction, furnishing polycyclic aromatics of various ring sizes in good yields.
- Yamada, Takayuki,Saito, Kodai,Akiyama, Takahiko
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supporting information
p. 62 - 66
(2016/01/25)
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- Use of Trifluoromethyl Groups for Catalytic Benzylation and Alkylation with Subsequent Hydrodefluorination
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The electrophilic organofluorophosphonium catalyst [(C6F5)3PF][B(C6F5)4] is shown to effect benzylation or alkylation by aryl and alkyl CF3 groups with subsequent hydrodefluorination, thus resulting in a net transformation of CF3 into CH2-aryl fragments. In the case of alkyl CF3 groups, Friedel-Crafts alkylation by the difluorocarbocation proceeded without cation rearrangement, in contrast to the corresponding reactions of alkyl monofluorides.
- Zhu, Jiangtao,Prez, Manuel,Caputo, Christopher B.,Stephan, Douglas W.
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supporting information
p. 1417 - 1421
(2016/02/14)
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- Mechanistic study of the samarium diiodide - N,N-dimethyl-2-aminoethanol reducing system
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The impact of N,N-dimethyl-2-aminoethanol (DMAE) on the reactivity of SmI2 is presented. The SmI2-DMAE reagent system is capable of reducing a range of substrates including alkyl halides, ketones, lactones, and arenes. Mechanistic studies on anthracene reduction are consistent with a system that proceeds through a highly ordered, early transition state requiring 2 equiv of DMAE and 1 equiv of anthracene and Sm(II).
- Chciuk, Tesia V.,Boland, Brian P.,Flowers, Robert A.
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supporting information
p. 3212 - 3215
(2015/03/05)
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- Electrophilic Fluorophosphonium Cations in Frustrated Lewis Pair Hydrogen Activation and Catalytic Hydrogenation of Olefins
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The combination of phosphorus(V)-based Lewis acids with diaryl amines and diaryl silylamines promotes reversible activation of dihydrogen and can be further exploited in metal-free catalytic olefin hydrogenation. Combined experimental and density functional theory (DFT) studies suggest a frustrated Lewis pair type activation mechanism. FLP hydrogenation: The combination of a phosphorus(V)-based Lewis acid with diaryl amines or diaryl silylamines promotes reversible activation of dihydrogen and can be further exploited in metal-free catalytic olefin hydrogenation. Combined experimental and density functional theory (DFT) studies suggest a frustrated Lewis pair (FLP)-type activation mechanism.
- Vom Stein, Thorsten,Perz, Manuel,Dobrovetsky, Roman,Winkelhaus, Daniel,Caputo, Christopher B.,Stephan, Douglas W.
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supporting information
p. 10178 - 10182
(2015/09/01)
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- Proton-Coupled Electron Transfer in the Reduction of Arenes by SmI2-Water Complexes
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The presence of water has a significant impact on the reduction of substrates by SmI2. The reactivity of the Sm(II)-water reducing system and the relationship between sequential or concerted electron-transfer, proton-transfer is not well understood. In this work, we demonstrate that the reduction of an arene by SmI2-water proceeds through an initial proton-coupled electron transfer. The use of thermochemical data available in the literature shows that upon coordination of water to Sm(II) in THF, significant weakening of the O-H bond occurs. The derived value of nearly 73 kcal/mol for the decrease in the bond dissociation energy of the O-H bond in the Sm(II)-water complex is the largest reported to date for low-valent reductants containing bound water.
- Chciuk, Tesia V.,Flowers, Robert A.
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supporting information
p. 11526 - 11531
(2015/09/21)
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- Deciphering a 20-Year-Old Conundrum: The Mechanisms of Reduction by the Water/Amine/SmI2 Mixture
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The reaction of SmI2 with the substrates 3-methyl-2-butanone, benzyl chloride, p-cyanobenzyl chloride, and anthracene were studied in the presence of water and an amine. In all cases, the water content versus rate profile shows a maximum at around 0.2 M H2O. The rate versus amine content profile shows in all cases, except for benzyl chloride, saturation behavior, which is typical of a change in the identity of the rate-determining step. The mechanism that is in agreement with the observed data is that electron transfer occurs in the first step. With substrates that are not very electrophilic, the intermediate radical anions lose the added electron back to samarium(III) relatively quickly and the reaction cannot progress efficiently. However, in a mixture of water/amine, the amine deprotonates a molecule of water coordinated to samarium(III). The negatively charged hydroxide, which is coordinated to samarium(III), reduces its electrophilicity, and therefore, lowers the rate of back electron transfer, which allows the reaction to progress. In the case of benzyl chloride, in which electron transfer is rate determining, deprotonation by the amine is coupled to the electron-transfer step.
- Maity, Sandeepan,Hoz, Shmaryahu
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supporting information
p. 18394 - 18400
(2015/12/24)
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- Heteroatom-free arene-cobalt and arene-iron catalysts for hydrogenations
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75 years after the discovery of hydroformylation, cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. We have evaluated arene metalates in which the low-valent metal species is - conceptually different from heteroatom-based ligands - stabilized by π coordination to hydrocarbons. Potassium bis(anthracene)cobaltate 1 and -ferrate 2 can be viewed as synthetic precursors of quasi-"naked" anionic metal species; their aggregation is effectively impeded by (labile) coordination to the various π acceptors present in the hydrogenation reactions of unsaturated molecules (alkenes, arenes, carbonyl compounds). Kinetic studies, NMR spectroscopy, and poisoning studies of alkene hydrogenations support the formation of a homogeneous catalyst derived from 1 which is stabilized by the coordination of alkenes. This catalyst concept complements the use of complexes with heteroatom donor ligands for reductive processes. Especially high selectivities were observed in the hydrogenation of various alkenes, ketones, and imines with bis(anthracene) cobaltate(-I) [K(dme)2{Co(C14H10)2}] under mild conditions (1-5 mol% cat., 1-10 bar H2, 20-60°C). Mechanistic studies indicate the operation in alkene hydrogenations of a homogeneous catalyst formed by initial ligand exchange and stabilized by the coordination of π-acidic alkenes or arenes.
- Gaertner, Dominik,Welther, Alice,Rad, Babak Rezaei,Wolf, Robert,Von Wangelin, Axel Jacobi
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supporting information
p. 3722 - 3726
(2014/04/17)
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- Determination of the effective redox potentials of SmI2, SmBr2, SmCl2, and their complexes with water by reduction of aromatic hydrocarbons. Reduction of anthracene and stilbene by samarium(II) iodide-water complex
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Samarium(II) iodide-water complexes are ideally suited to mediate challenging electron transfer reactions, yet the effective redox potential of these powerful reductants has not been determined. Herein, we report an examination of the reactivity of SmI2(H2O)n with a series of unsaturated hydrocarbons and alkyl halides with reduction potentials ranging from -1.6 to -3.4 V vs SCE. We found that SmI 2(H2O)n reacts with substrates that have reduction potentials more positive than -2.21 V vs SCE, which is much higher than the thermodynamic redox potential of SmI2(H2O) n determined by electrochemical methods (up to -1.3 V vs SCE). Determination of the effective redox potential demonstrates that coordination of water to SmI2 increases the effective reducing power of Sm(II) by more than 0.4 V. We demonstrate that complexes of SmI2(H 2O)n arising from the addition of large amounts of H 2O (500 equiv) are much less reactive toward reduction of aromatic hydrocarbons than complexes of SmI2(H2O)n prepared using 50 equiv of H2O. We also report that SmI 2(H2O)n cleanly mediates Birch reductions of substrates bearing at least two aromatic rings in excellent yields, at room temperature, under very mild reaction conditions, and with selectivity that is not attainable by other single electron transfer reductants.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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p. 2522 - 2537
(2014/04/17)
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- Hydroxylated HMPA enhances both reduction potential and proton donation in SmI2 reactions
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HMPA is known to increase the reduction potential of SmI2. However, in many cases, the transferred electron returns from the radical anion of the substrate back to the Sm3+. This could be avoided by an efficient trapping of the radical anion: e.g., by protonation. However, bimolecular protonation by a proton donor from the bulk may be too slow to compete with the back electron transfer process. An efficient unimolecular protonation could be achieved by using a proton donor which complexes to SmI2, in which case the proton is unimolecularly transferred within the ion pair. A derivative of HMPA in which one of the methyl groups was substituted by a CH2CH2OH unit was synthesized. Cyclic voltammetry studies have shown that it resembles HMPA in its ability to enhance the reduction potential of SmI2, and reactivity studies show that it has also efficient proton shift capabilities. The various aspects of this additive were examined in the reactions of SmI2 with three substrates: benzyl chloride, methyl cinnamate, and anthracene.
- Halder, Sandipan,Hoz, Shmaryahu
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p. 2682 - 2687
(2014/04/17)
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- Combinations of ethers and B(C6F5)3 function as hydrogenation catalysts
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It works ether way: Labile adducts of dialkyl ethers with the electrophilic borane B(C6F5)3 are shown to scramble HD to H2 and D2 and catalyze the hydrogenation of 1,1-diphenylethylene. Copyright
- Hounjet, Lindsay J.,Bannwarth, Christoph,Garon, Christian N.,Caputo, Christopher B.,Grimme, Stefan,Stephan, Douglas W.
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supporting information
p. 7492 - 7495
(2013/07/26)
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- Quenched skeletal Ni as the effective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons
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Quenched skeletal Ni is an active and selective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons (PAHs). The molecular structure of PAHs significantly dominate the hydrogenation process and furthermore, the distribution of hydrogenated products.
- Liu, Chengyun,Rong, Zeming,Sun, Zhuohua,Wang, Yong,Du, Wenqiang,Wang, Yue,Lu, Lianhai
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p. 23984 - 23988
(2013/11/19)
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- Formation of the cobalt hydrogenation catalysts at the action of lithium aluminum hydride and lithium tri(tert-butoxy)aluminohydride and their properties
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The interaction of Co(acac)2(3) with LiAlH4 or LiAlH(t-BuO)3 was studied using NMR, UV, IR, ESR spectroscopy, electron microscopy, and volumometry. The basic stages of formation of cobalt catalysts for hydrogenation were suggested. The formation of the nanoparticles that are active in the hydrogenation process is shown to occur at a ratio of reagents 5 ≤ Red/Co ≤ 12. The nanoparticles are stabilized by an excess of LiAlH4 or LiAlH(t-BuO)3, as well as by the products of their catalytic decomposition under the action of cobalt in the reduced state. At the ratio LiAlH4 / Co> 12 to obtain the particles active in catalysis their activation by a proton-donor compound is required.
- Schmidt, F. K.,Titova, Yu.,Umanets, V. A.,Khutsishvili, S. S.,Belykh, L. B.
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p. 1334 - 1341,8
(2020/09/16)
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- Cu-Promoted [2 + 2] cycloaddition of 1,4-bisallenes
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The thermal reaction of 1,4-bisallenes with the aid of Cu salt/amine significantly suppressed the formal [3,3] sigmatropic rearrangement resulting in the highly selective formation of the bicyclo[4.2.0]octadiene framework. This reaction could be applied to the one-pot synthesis of bicyclo[4.2.0]octadienes from 1,5-hexadiynes via the Crabbe homologation.
- Kitagaki, Shinji,Kajita, Mikihito,Narita, Syu,Mukai, Chisato
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supporting information; experimental part
p. 1366 - 1369
(2012/05/20)
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