- Catalytic fixation of CO2 to cyclic carbonates by phosphonium chlorides immobilized on fluorous polymer
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Phosphonium chloride covalently bound to the fluorous polymer is proved to be an efficient and recyclable homogeneous CO2-soluble catalyst for organic solvent-free synthesis of cyclic carbonates from epoxides and CO 2 under supercrit
- Song, Qing-Wen,He, Liang-Nian,Wang, Jin-Quan,Yasuda, Hiroyuki,Sakakura, Toshiyasu
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- Organocatalytic carbon dioxide fixation to epoxides by perfluorinated 1,3,5-triols catalysts
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In order to improve epoxides conversion to carbonates by fixation of CO2 a new type of perfluorinated triol catalysts was developed. These simple acyclic scaffolds of enhanced acidity are efficient for catalysis through selective H-bonding acti
- Quintard, Adrien,Rodriguez, Jean,Sperandio, Céline
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- DBU/benzyl bromide: An efficient catalytic system for the chemical fixation of CO2 into cyclic carbonates under metal- and solvent-free conditions
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A simple, mild, and inexpensive catalytic system consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and benzyl bromide was developed for the cycloaddition of epoxides with ambient CO2 under metal-free and solvent-free conditions. Moreover,
- Wang, Lin,Kodama, Koichi,Hirose, Takuji
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- A poly(ethylene glycol)-supported quaternary ammonium salt for highly efficient and environmentally friendly chemical fixation of CO2 with epoxides under supercritical conditions
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A PEG-supported quaternary ammonium salt is proved to be an efficient and recyclable homogeneous catalyst for solvent-free synthesis of cyclic carbonates from carbon dioxide and epoxides under supercritical conditions. Supporting Bu4NBr on solu
- Du, Ya,Wang, Jin-Quan,Chen, Jian-Yu,Cai, Fei,Tian, Jie-Sheng,Kong, De-Lin,He, Liang-Nian
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- Preparation of MOF Film/Aerogel Composite Catalysts via Substrate-Seeding Secondary-Growth for the Oxygen Evolution Reaction and CO2 Cycloaddition
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Substrate-supported metal–organic frameworks (MOFs) films are desired to realize their potential in practical applications. Herein, a novel substrate-seeding secondary-growth strategy is developed to prepare composites of uniform MOFs films on aerogel wal
- Bai, Xiao-Jue,Lu, Xing-Yu,Ju, Ran,Chen, Huan,Shao, Lei,Zhai, Xu,Li, Yu-Nong,Fan, Fu-Qiang,Fu, Yu,Qi, Wei
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- Construction of an Asymmetric Porphyrinic Zirconium Metal-Organic Framework through Ionic Postchiral Modification
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Herein, one kind of neutral chiral zirconium metal-organic framework (Zr-MOF) was reported from the porphyrinic MOF (PMOF) family with a metallolinker (MnIII-porphyrin) as the achiral polytopic linker [free base tetrakis(4-carboxyphenyl)porphyrin] and chiral anions. Achiral Zr-MOF was chiralized through the exchange of primitive anions with new chiral organic anions (postsynthetic exchange). This chiral functional porphyrinic MOF (CPMOF) was characterized by several techniques such as powder X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, 1H NMR, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and Brunauer-Emmett-Teller measurements. In the resulting structure, there are two active metal sites as Lewis acid centers (Zr and Mn) and chiral species as Br?nsted acid sites along with their cooperation as nucleophiles. This CPMOF shows considerable bimodal porosity with high surface area and stability. Additionally, its ability was investigated in asymmetric catalyses of prochiral substrates. Interactions between framework chiral species and prochiral substrates have large impacts on the catalytic ability and chirality induction. This chiral catalyst proceeded asymmetric epoxidation and CO2 fixation reactions at lower pressure with high enantioselectivity due to Lewis acids and chiral auxiliary nucleophiles without significant loss of activity up to the sixth step of consecutive cycles of reusability. Observations revealed that chiralization of Zr-MOF could happen by a succinct strategy that can be a convenient method to design chiral MOFs.
- Berijani, Kayhaneh,Morsali, Ali
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p. 206 - 218
(2021/01/11)
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- Synthesis and a Catalytic Study of Diastereomeric Cationic Chiral-at-Cobalt Complexes Based on (R, R)-1,2-Diphenylethylenediamine
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Here we report the first synthesis of two diastereomeric cationic octahedral Co(III) complexes based on commercially available (R,R)-1,2-diphenylethylenediamine and salicylaldehyde. Both diastereoisomers with opposite chiralities at the metal center (Λ and Δconfigurations) were prepared. The new Co(III) complexes possessed both acidic hydrogen-bond donating (HBD) NH moieties and nucleophilic counteranions and operate as bifunctional chiral catalysts for the challenging kinetic resolution of terminal and disubstituted epoxides by the reaction with CO2 under mild conditions. The highest selectivity factor (s) of 2.8 for the trans-chalcone epoxide was achieved at low catalyst loading (2 mol %) in chlorobenzene, which is the best achieved result currently for this type of substrate.
- Emelyanov, Mikhail A.,Stoletova, Nadezhda V.,Smol'Yakov, Alexander F.,Il'In, Mikhail M.,Maleev, Victor I.,Larionov, Vladimir A.
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p. 13960 - 13967
(2021/09/11)
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- Catalytic, Kinetic, and Mechanistic Insights into the Fixation of CO2 with Epoxides Catalyzed by Phenol-Functionalized Phosphonium Salts
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A series of hydroxy-functionalized phosphonium salts were studied as bifunctional catalysts for the conversion of CO2 with epoxides under mild and solvent-free conditions. The reaction in the presence of a phenol-based phosphonium iodide proceeded via a first order rection kinetic with respect to the substrate. Notably, in contrast to the aliphatic analogue, the phenol-based catalyst showed no product inhibition. The temperature dependence of the reaction rate was investigated, and the activation energy for the model reaction was determined from an Arrhenius-plot (Ea=39.6 kJ mol?1). The substrate scope was also evaluated. Under the optimized reaction conditions, 20 terminal epoxides were converted at room temperature to the corresponding cyclic carbonates, which were isolated in yields up to 99 %. The reaction is easily scalable and was performed on a scale up to 50 g substrate. Moreover, this method was applied in the synthesis of the antitussive agent dropropizine starting from epichlorohydrin and phenylpiperazine. Furthermore, DFT calculations were performed to rationalize the mechanism and the high efficiency of the phenol-based phosphonium iodide catalyst. The calculation confirmed the activation of the epoxide via hydrogen bonding for the iodide salt, which facilitates the ring-opening step. Notably, the effective Gibbs energy barrier regarding this step is 97 kJ mol?1 for the bromide and 72 kJ mol?1 for the iodide salt, which explains the difference in activity.
- Hu, Yuya,Wei, Zhihong,Frey, Anna,Kubis, Christoph,Ren, Chang-Yue,Spannenberg, Anke,Jiao, Haijun,Werner, Thomas
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p. 363 - 372
(2020/11/30)
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- Method for preparing cyclic carbonate by immobilizing CO2 under catalysis of organic boric acid
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The invention discloses a synthesis method for synergistically catalyzing carbon dioxide immobilization through weak Lewis acid phenylboronic acid and tetrabutylammonium bromide. According to the method, CO2 is immobilized by epoxide, and a cyclic carbonate product is generated. The method comprises the following step: under the concerted catalysis of phenylboronic acid and tetrabutylammonium bromide, performing reaction on epoxide as shown in a formula IV, a formula V or a formula VI and carbon dioxide to respectively obtain a cyclic carbonate product as shown in a formula I, a formula II or a formula III. According to the method, raw materials are convenient and easy to obtain, reaction conditions are mild, operation is easy and convenient, and the yield can reach 97%.
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Paragraph 0221-0226
(2021/06/22)
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- Synthesis of Ionic Liquids as Novel Nanocatalysts for Fixation of Carbon Dioxide with Epoxides by Using a Carbon Dioxide Balloon
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Abstract: In the present study, the nanocatalyst of imidazolium based ionic liquids (ILs) is synthesized for the fixation of carbon dioxide (CO2) under moderate conditions by utilizing a balloon of CO2 with commercially available epoxides. IL incorporated porous dendritic fibrous nanosilica (DFNS) catalyst (IL/DFNS) was designed and synthesized. The synthesized catalyst was characterized using N2 absorption desorption isotherm, XPS, SEM, EDX, TGA, HR-TEM, and AFM. For cyclic carbonate, an environmental friendly catalyst of porous IL/DFNS indicate highly impressive catalytic efficiency from CO2 through CO2 fixation and epoxides under mild condition. Attendance of polar hydroxyl and anion exchange nature groups of IL frame work to high surface area is known as the main aspect to be reliable for elevated catalytic efficiency and also advance in stability of catalyst and providing a proper recyclability. Graphic Abstract: [Figure not available: see fulltext.].
- Zhang, Pu,Zhiani, Rahele
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p. 2254 - 2266
(2020/02/18)
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- Bimetallic scorpionate-based helical organoaluminum complexes for efficient carbon dioxide fixation into a variety of cyclic carbonates
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A new family of bimetallic helical aluminum complexes can be obtainedviawarming up the preliminary dinuclear adduct complexes, or alternatively, by direct heating of the protioligands with 2 equiv. of AlR3. X-ray diffraction analysis corroborat
- Fernández, Israel,Fernández-Baeza, Juan,Garcés, Andrés,Lara-Sánchez, Agustín,Navarro, Marta,Rodríguez, Ana M.,Sánchez-Barba, Luis F.
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p. 3265 - 3278
(2020/06/17)
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- Kinetic Resolution of Epoxides with CO2 Catalyzed by a Chiral-at-Iridium Complex
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Chiral-at-metal bis-cyclometalated iridium(III) complexes are introduced as a new class of chiral catalysts for the reaction of epoxides with CO2 to form cyclic carbonates under conditions of kinetic resolution. Reactions are typically performed at room temperature in the presence of 1 mol % of iridium catalyst and 1.5 mol % of tetraethylammonium bromide as the nucleophilic cocatalyst to provide selectivity factors of up to 16.6. A variety of monosubstituted epoxides, including styrene epoxide, epoxides with aliphatic side chains, glycidyl ethers, and a glycidyl ester, are found to be suitable substrates. No polymerization side reaction is observed for any of the investigated substrates.
- Qin, Jie,Larionov, Vladimir A.,Harms, Klaus,Meggers, Eric
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p. 320 - 325
(2018/11/27)
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- Bifunctional phase-transfer catalysts for fixation of CO2 with epoxides under ambient pressure
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A series of bifunctional phase-transfer catalysts with a quaternary onium center and a hydrogen-bonding donor group were prepared for the fixation of CO2 with commercially available epoxides under mild conditions by using a CO2 balloon (1 atm). In the presence of 2.5 mol% of achiral bifunctional phase-transfer catalysts, cyclic carbonates were obtained in good to excellent yields (up to 95%). Additionally, optical carbonates and epoxides were obtained through the kinetic resolution of rac-epoxides by 1 mol% of chiral bifunctional phase-transfer catalysts with low enantioselectivities. These catalysts featured a simple synthetic route, good modularity and high efficiency.
- Li, Yue-Dan,Cui, Dong-Xiao,Zhu, Jun-Chao,Huang, Ping,Tian, Zhuang,Jia, Yan-Yan,Wang, Ping-An
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supporting information
p. 5231 - 5237
(2019/10/11)
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- Highly regio- And stereoselective synthesis of cyclic carbonates from biomass-derived polyols: Via organocatalytic cascade reaction
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The cascade reaction of CO2, vicinal diols, and propargylic alcohol, was firstly achieved by dual Lewis base (LB) organocatalytic systems involving LB-CO2 adducts and commercially available organic amines. This methodology could overcome the chemical inertness of CO2, providing an alternative route to various functionalized five-membered cyclic carbonates in moderate to high yields under mild reaction conditions (25 °C, 1.0 atm of CO2). More importantly, this method could also be applied for facile and efficient synthesis of chiral polycyclic carbonates from biomass-derived polyols with complete configuration retention of chiral centers. This study provides an environment-friendly, scalable and cost effective protocol to construct value-added cyclic carbonates with multi-functional groups and chiral centers.
- Zhou, Hui,Zhang, Hui,Mu, Sen,Zhang, Wen-Zhen,Ren, Wei-Min,Lu, Xiao-Bing
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supporting information
p. 6335 - 6341
(2019/12/03)
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- Chiral Bifunctional Metalloporphyrin Catalysts for Kinetic Resolution of Epoxides with Carbon Dioxide
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Chiral binaphthyl-strapped Zn(II) porphyrins with triazolium halide units were synthesized as bifunctional catalysts for kinetic resolution of epoxides with CO2. Several catalysts were screened by changing the linker length and nucleophilic counteranions, and the optimized catalyst accelerated the enantioselective reaction at ambient temperature to produce optically active cyclic carbonates and epoxides.
- Maeda, Chihiro,Mitsuzane, Mayato,Ema, Tadashi
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supporting information
p. 1853 - 1856
(2019/03/11)
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- A novel homochiral metal-organic framework with an expanded open cage based on (: R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl: synthesis, X-ray structure and efficient HPLC enantiomer separation
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A new homochiral metal-organic framework (MOF) with an expanded open cage based on the (R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl ligand was synthesized and utilized as a novel chiral stationary phase for high-performance liquid chromatography. Twelve racemates including sec-alcohols, sulfoxides, epoxides, lactone, 1,3-dioxolan-2-one, and oxazolidinone were used as analytes for evaluating the separation properties of the chiral-MOF-packed column. Experimentally, the homochiral MOF offered good molecular recognition ability, which suggests good prospects for the application of chiral MOFs as stationary phases for enantioseparation.
- Tanaka, Koichi,Kawakita, Tomohiro,Morawiak, Maja,Urbanczyk-Lipkowska, Zofia
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p. 487 - 493
(2019/01/21)
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- Hemisquaramide Tweezers as Organocatalysts: Synthesis of Cyclic Carbonates from Epoxides and CO2
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Hemisquaramide tweezers, a new family of H-bond donor organocatalysts, are reported. The catalysts could be synthesized within two steps. Among them, H8-binaphthyl-linked hemisquaramide 7 markedly accelerated the synthesis of cyclic carbonates from epoxides and CO2. The reactions proceeded well under mild and solvent-free conditions. Kinetic resolution was also achieved at -20 °C (s = 3.0). The adjustable bite angle and orientation of the two NH groups of the catalysts are important for the high activity.
- Takaishi, Kazuto,Okuyama, Takafumi,Kadosaki, Shota,Uchiyama, Masanobu,Ema, Tadashi
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supporting information
p. 1397 - 1401
(2019/02/26)
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- Chiroptical and catalytic properties of doubly binaphthyl-strapped chiral porphyrins
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Doubly (R)-binaphthyl-strapped porphyrins with methylene chains were synthesized. The CD spectra showed the positive Cotton effect around the Soret bands, and several porphyrins showed CPL. In addition, we found that the chiral porphyrins were applicable to kinetic resolution of epoxide with CO2.
- Maeda, Chihiro,Ogawa, Kanae,Sadanaga, Kosuke,Takaishi, Kazuto,Ema, Tadashi
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supporting information
p. 1064 - 1067
(2019/01/28)
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- Unexpected Macrocyclic Multinuclear Zinc and Nickel Complexes that Function as Multitasking Catalysts for CO2 Fixations
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Unique self-assembled macrocyclic multinuclear ZnII and NiII complexes with binaphthyl-bipyridyl ligands (L) were synthesized. X-ray analysis revealed that these complexes consisted of an outer ring (Zn3L3 or Ni3L3) and an inner core (Zn2 or Ni). In the ZnII complex, the inner Zn2 part rotated rapidly inside the outer ring in solution on an NMR timescale. These complexes exhibited dual catalytic activities for CO2 fixations: synthesis of cyclic carbonates from epoxides and CO2 and temperature-switched N-formylation/N-methylation of amines with CO2 and hydrosilane.
- Takaishi, Kazuto,Nath, Bikash Dev,Yamada, Yuya,Kosugi, Hiroyasu,Ema, Tadashi
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supporting information
p. 9984 - 9988
(2019/06/24)
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- Development of Isostructural Porphyrin-Salen Chiral Metal-Organic Frameworks through Postsynthetic Metalation Based on Single-Crystal to Single-Crystal Transformation
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The development of well-defined multimetallic porous metal-organic frameworks (MOFs) will add a new dimension to the application of MOF catalysis. From this perspective, the understanding and tailoring of the catalytic metal sites in MOFs are key fundamental challenges that could reveal the intrinsic potential of these materials. In this work, a series of porphyrin-salen chiral MOFs (ps-CMOFs 2-7) have been synthesized through postsynthetic metalation (PSMet) of the parent ps-CMOF via single-crystal to single-crystal transformation. Crystal structures of these ps-CMOF analogues revealed the same topological structure but varied metal entities compared to those of the parent framework. Note that the PSMet process involves three methods involving cation exchange at the nodes, cation exchange at the metalated porphyrin, and cation addition at the free porphyrin, which has been systematically investigated using single-crystal X-ray diffraction and other physicochemical methods. The N2 adsorption tests, thermogravimetric analysis, and powder X-ray diffraction of 2-7 showed curves or patterns similar to those of 1, indicating the maintenance of the crystallinity, porosity, and thermal stability of the framework during the PSMet process. In addition, 2-7 showed distinctly improved adsorption capacities and isosteric heats of adsorption (Qst) for CO2 compared to those of their parent counterpart. Lastly, as a representative example of the ps-CMOF catalytic platform, 5 proved to be an efficient recyclable heterogeneous catalyst for the asymmetric addition reaction of CO2 with epoxides under mild conditions. Furthermore, because of the constrained chiral environment within ps-CMOF, the enantioselectivity of this reaction appears to be dependent on substrate size.
- Li, Jiawei,Fan, Yamei,Ren, Yanwei,Liao, Jianhua,Qi, Chaorong,Jiang, Huanfeng
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p. 1203 - 1212
(2018/02/14)
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- Chiral basket-handle porphyrin-Co complexes for the catalyzed asymmetric cycloaddition of CO2 to epoxides
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The catalytic synthesis of cyclic carbonates via the cycloaddition of CO2 to epoxides is a standard methodology for CO2 fixation. For this purpose, chiral basket-handle porphyrin-Co complexes were devised, prepared, and fully characterized by nuclear magnetic resonance, mass spectrometry, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and specific rotation. The proposed metalloporphyrin catalysts were synthesized with either 1,1′-bi-2-naphthol or L-phenylalanine, which have different chirality, and then applied to the coupling of propylene oxide and CO2 for generating chiral cyclic carbonates with good enantioselectivity under extremely mild conditions in the presence of tetrabutyl ammonium chloride as a co-catalyst. The good enantioselectivity in the cycloaddition reaction is attributed to a synergistic interplay between the chiral porphyrin catalysts and the substrate. The mechanism and enantioselectivity of the asymmetric cycloaddition reaction is discussed.
- Fu, Xiying,Jing, Xinyao,Jin, Lili,Zhang, Lilong,Zhang, Xiaofeng,Hu, Bin,Jing, Huanwang
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p. 997 - 1003
(2018/05/23)
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- Synthesis of Cyclic Organic Carbonates Using Atmospheric Pressure CO2 and Charge-Containing Thiourea Catalysts
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Cycloadditions of epoxides with CO2 to synthesize cyclic five-membered ring organic carbonates are of broad interest from a synthetic, environmental, and green chemistry perspective, and the development of effective catalysts for these transformations is an ongoing challenge. A series of eight charge-containing thiourea salts that catalyze these reactions under mild conditions (i.e., 60 °C and atmospheric CO2 pressure) are reported. Substrate scope and mechanistic studies were also carried out, isotope effects were measured, and a reactive intermediate was isolated revealing a surprising pathway in which a thiourea catalyst serves as a nucleophile in the cleavage of the epoxide ring.
- Fan, Yang,Tiffner, Maximilian,Sch?rgenhumer, Johannes,Robiette, Rapha?l,Waser, Mario,Kass, Steven R.
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p. 9991 - 10000
(2018/07/30)
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- Cooperative Multifunctional Organocatalysts for Ambient Conversion of Carbon Dioxide into Cyclic Carbonates
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A series of pincer-type compounds possessing an N-heterocyclic carbene precursor and a carboxyl group as proton transfer agent were synthesized and used as organocatalysts for the cycloaddition of epoxides with CO2. In this context, we have demonstrated the high activity of these one-component organocatalysts in the CO2 transformation to cyclic carbonates under ambient conditions (room temperature, 1 bar of CO2). The catalytic potential of these multifunctional organocatalysts on challenging internal epoxides is particularly deserving of mention because organocatalysts that are able to mediate the cycloaddition reaction of internal epoxides with CO2 under mild conditions remain scarce. The intramolecular synergistic activation mechanism was elucidated by control experiments and DFT calculations.
- Liu, Ning,Xie, Ya-Fei,Wang, Chuan,Li, Shi-Jun,Wei, Donghui,Li, Min,Dai, Bin
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p. 9945 - 9957
(2018/10/15)
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- Covalent organic frameworks: Efficient, metal-free, heterogeneous organocatalysts for chemical fixation of CO2 under mild conditions
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The cycloaddition of CO2 to epoxides to form cyclic carbonates is very promising and does not generate any side products. Metal-free, heterogeneous organocatalysts offer an environmentally friendly alternative to traditional metal-based catalysts. Herein two triazine-based covalent organic frameworks (COF-JLU6 and COF-JLU7) were successfully synthesized under solvothermal conditions. The structural and chemical properties of COFs were fully characterized by using powder X-ray diffraction analysis, structural simulation, Fourier transform infrared spectroscopy, 13C solid-state NMR spectroscopy, electron microscopy, thermogravimetric analysis and nitrogen adsorption. The two COF materials combine mesopores, high crystallinity and good stability, as well as a large number of hydroxy groups in the pore walls. They possess a high Brunauer-Emmett-Teller (BET) specific surface area up to 1390 m2 g-1 and a large pore volume of 1.78 cm3 g-1. The COF-JLU7 displays a high CO2 uptake of 151 mg g-1 at 273 K and 1 bar. Importantly, COF-JLU7 was found to be a highly effective catalyst to convert CO2 into cyclic carbonate through the cycloaddition reaction with epoxides under mild conditions. The effect of reaction parameters, such as reaction temperature, reaction time and CO2 pressure, on the catalytic performance was also investigated in detail. Moreover, the new framework-based catalyst can be recovered and reused five times without a significant loss of catalytic efficiency.
- Zhi, Yongfeng,Shao, Pengpeng,Feng, Xiao,Xia, Hong,Zhang, Yumin,Shi, Zhan,Mu, Ying,Liu, Xiaoming
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supporting information
p. 374 - 382
(2018/01/12)
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- Asymmetric Allylic C-H Alkylation via Palladium(II)/ cis-ArSOX Catalysis
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We report the development of Pd(II)/cis-aryl sulfoxide-oxazoline (cis-ArSOX) catalysts for asymmetric C-H alkylation of terminal olefins with a variety of synthetically versatile nucleophiles. The modular, tunable, and oxidatively stable ArSOX scaffold is key to the unprecedented broad scope and high enantioselectivity (37 examples, avg. > 90% ee). Pd(II)/cis-ArSOX is unique in its ability to effect high reactivity and catalyst-controlled diastereoselectivity on the alkylation of aliphatic olefins. We anticipate that this new chiral ligand class will find use in other transition metal catalyzed processes that operate under oxidative conditions.
- Liu, Wei,Ali, Siraj Z.,Ammann, Stephen E.,White, M. Christina
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p. 10658 - 10662
(2018/09/06)
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- Activation of (salen)CoI complex by phosphorane for carbon dioxide transformation at ambient temperature and pressure
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We report the activation of (salen)CoI complex 3g by a phosphorane to form a bifunctional catalyst for the reaction of carbon dioxide with terminal epoxides or aziridines at ambient temperature and 1 bar carbon dioxide pressure. Only 1.0 mol% of both (salen)CoI 3g and phosphorane 4d are required for cyclic carbonate synthesis, and the catalyst loading could even be lowered down to 0.1 mol%. Under these conditions, no polycarbonate formation is detected by NMR analysis. It is proposed that the high efficiency originates from the activation of (salen)CoI by a phosphorane to form a phosphorane-salen Co(iii) complex with enhanced Lewis acidity for the electrophilic activation while generating an iodide anion as a Lewis base co-catalyst to facilitate the ring-opening of epoxides. Further investigation revealed that the phosphorane-(salen)CoI complex could also successfully catalyze the coupling of CO2 with aziridines under ambient conditions at a catalyst loading of 2.5 mol%.
- Zhou, Feng,Xie, Shi-Liang,Gao, Xiao-Tong,Zhang, Rong,Wang, Cui-Hong,Yin, Guang-Qiang,Zhou, Jian
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p. 3908 - 3915
(2017/08/22)
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- Salen(Co(III)) imprisoned within pores of a metal-organic framework by post-synthetic modification and its asymmetric catalysis for CO2 fixation at room temperature
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Herein, a new preparation strategy of chiral metal-organic frameworks (CMOFs) has been demonstrated. By adsorption and then post-synthetically modified (PSM) procedures, chiral salen(Co(iii)) could be imprisoned within the cages of an MOF and remained in its free form. This is the first report on the successful application of CMOFs in heterogeneous asymmetric catalysis for coupling CO2 with epoxides to obtain optically active cyclic carbonates at room temperature.
- Chen, Danping,Luo, Ran,Li, Meiyan,Wen, Mengqi,Li, Yan,Chen, Chao,Zhang, Ning
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p. 10930 - 10933
(2017/10/11)
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- An in situ formed Ca2+-crown ether complex and its use in CO2-fixation reactions with terminal and internal epoxides
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Herein we report an efficient catalytic system based on readily available calcium iodide and 18-crown-6 ether for the atom economical addition of CO2 to epoxides. 1H NMR experiments revealed the selective in situ formation of a crown ether complex. This catalyst allows the conversion of various terminal epoxides under 1 atm CO2 pressure even at room temperature. Remarkably, a broad range of internal epoxides with various substitution patterns and substituents were smoothly converted which confirms the high efficiency and capability of the protocol. Notably, most of the internal carbonates were synthesized in high yields and diastereoselectivities of up to ≥99%. Furthermore, this system operates under solvent-free conditions without any co-catalysts e.g. onium salts.
- Steinbauer,Spannenberg,Werner
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supporting information
p. 3769 - 3779
(2017/08/26)
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- Poly(ethylene glycol)s as Ligands in Calcium-Catalyzed Cyclic Carbonate Synthesis
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Herein the use of CaI2 in combination with poly(ethylene glycol) dimethyl ether (PEG DME 500) as an efficient catalyst system for the addition of CO2 to epoxides is reported. This protocol is based on a nontoxic and abundant metal in conjunction with a polymeric ligand. Fifteen terminal epoxides were converted at room temperature to give the desired products in yields up to 99 %. Notably, this system was also effective for the synthesis of twelve challenging internal carbonates in yields up to 98 %.
- Steinbauer, Johannes,Werner, Thomas
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p. 3025 - 3029
(2017/08/18)
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- Efficient and practical organocatalytic system for the synthesis of?cyclic carbonates from carbon dioxide and epoxides: 3-hydroxypyridine/tetra-n-butylammonium iodide
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An efficient and practical organocatalytic system comprising 3-hydroxypyridine and tetra-n-butylammonium iodide was developed for the synthesis of cyclic carbonates from carbon dioxide and epoxides under mild conditions (1?atm CO2, 25–60?°C) wi
- Wang, Xiangyong,Wang, Lin,Zhao, Yingying,Kodama, Koichi,Hirose, Takuji
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supporting information
p. 1190 - 1195
(2017/02/05)
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- Pushing the Limits with Squaramide-Based Organocatalysts in Cyclic Carbonate Synthesis
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Squaramides are presented as modular, easy to optimize, and effective catalysts for the conversion of epoxides and carbon dioxide into cyclic organic carbonates (COCs). The catalytic potential of these squaramides, in combination with a suitable halide nucleophile, is particularly noted when internal epoxides are examined as substrates, and their transformation into disubstituted COCs marks a rare case of an effective organocatalyst for these challenging conversions. Control experiments support the mechanistic view that the squaramides are predominantly involved in the stabilization of intermediate oxo and carbonato anions which, after their formation, are able to displace a bromide nucleophile from an initially formed 1:1 assembly comprising the squaramide host.
- Sope?a, Sergio,Martin, Eddy,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
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p. 3532 - 3539
(2017/06/09)
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- Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
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New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
- Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
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supporting information
p. 3990 - 4001
(2017/11/22)
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- Chiral Macrocyclic Organocatalysts for Kinetic Resolution of Disubstituted Epoxides with Carbon Dioxide
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Among chiral macrocycles 1 synthesized, 1m with the 3,5-bis(trifluoromethyl)phenylethynyl group was the best organocatalyst for the enantioselective synthesis of cyclic carbonates from disubstituted or monosubstituted epoxides and CO2. The X-ray crystal structure of 1m revealed a well-defined chiral cavity with multiple hydrogen-bonding sites that is suitable for the enantioselective activation of epoxides. A catalytic cycle proposed was supported by DFT calculations.
- Ema, Tadashi,Yokoyama, Maki,Watanabe, Sagiri,Sasaki, Sota,Ota, Hiromi,Takaishi, Kazuto
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supporting information
p. 4070 - 4073
(2017/08/15)
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- Catalytic asymmetric cycloaddition of CO2 to epoxides via chiral bifunctional ionic liquids
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A series of new chiral ionic liquid catalysts composed of the N,N'-bis(salicyclidene) cyclohexene diaminatocobalt and an imidazolium salt were designed, prepared and applied for the chiral cyclic carbonate synthesis from racemic epoxides and carbon dioxide. All reactions exhibit good enantioselectivity for the chiral cyclic carbonate without polycarbonate and other by-products. The order of The order of catalytic activity toward the axial anions is OAc- > CF3CO2- > CCl3CO2- > OTs- and the order of enantioselectivity is OTs- > OAc- > CCl3CO2- > CF3CO2-.
- Duan, Shuhui,Jing, Xinyao,Li, Dandan,Jing, Huanwang
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- Three powerful dinuclear metal-organic catalysts for converting CO2 into organic carbonates
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Developing efficient catalysts for converting carbon dioxide (CO2) into varied organic carbonates is an important scientific goal. By using the NH2-functionalized tripodal ligand 2-((bis(2-aminoethyl)amino)methyl)phenol (HL), three dinuclear metal-organic complexes [Zn(L)]2·2ClO4 (1), [Cu(L)]2·2ClO4·2H2O (2) and [Cd(L)]2·2ClO4 (3) have been successfully isolated and structurally characterized using single-crystal X-ray diffraction analyses. Considering the dinuclear metal centers and the NH2-functional groups in the structures, 1-3 were investigated as catalysts for converting CO2 into organic carbonates, and the results show that 1-3 exhibit an outstanding ability for converting CO2 into varied organic carbonates at atmospheric pressure (0.1 MPa). The catalytic system also displays a wide substrate scope and high catalytic activity, and the reaction mechanism has been proposed herein.
- Zhao, Dan,Liu, Xiao-Hui,Shi, Zhuang-Zhi,Zhu, Chen-Dan,Zhao, Yue,Wang, Peng,Sun, Wei-Yin
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p. 14184 - 14190
(2016/11/05)
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- Chiral oligomers of spiro-salencobalt(III)X for catalytic asymmetric cycloaddition of epoxides with CO2
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Several new chiral oligomers of spiro-salenCo(III)X (spiro = 1.1′-spirobiindane-7.7′-diol) complexes have been designed, synthesized, and characterized by nuclear magnetic resonance (NMR), infrared (IR), and elemental analyses, in which, the chiral spiro moieties are first introduced into a scaffold of chiral salenCo catalysts. They were used to catalyze the asymmetric cycloaddition of epoxides with carbon dioxide. Under very mild reaction conditions, a kinetic resolution of racemic epoxides with CO2 was smoothly initiated by these chiral oligomer catalysts with good enantioselectivities, which can be attributed to the match effect between chiral backbones of salen and spiro. High stability and easy recyclability are their major advantages.
- Zhu, Zhouhe,Zhang, Yuqian,Wang, Kai,Fu, Xiying,Chen, Fengjuan,Jing, Huanwang
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- An efficient metal- and solvent-free organocatalytic system for chemical fixation of CO2 into cyclic carbonates under mild conditions
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An efficient, metal- and solvent-free catalytic system was developed for the conversion of CO2 and epoxides to the corresponding cyclic carbonates under mild conditions (T = 25-45 °C, 1 atm CO2) in high-to-excellent yields. The catal
- Wang, Lin,Zhang, Guangyou,Kodama, Koichi,Hirose, Takuji
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supporting information
p. 1229 - 1233
(2016/03/09)
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- Unprecedented Carbonato Intermediates in Cyclic Carbonate Synthesis Catalysed by Bimetallic Aluminium(Salen) Complexes
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The mechanism by which [Al(salen)]2O complexes catalyse the synthesis of cyclic carbonates from epoxides and carbon dioxide in the absence of a halide cocatalyst has been investigated. Density functional theory (DFT) studies, mass spectrometry and 1H NMR, 13C NMR and infrared spectroscopies provide evidence for the formation of an unprecedented carbonato bridged bimetallic aluminium complex which is shown to be a key intermediate for the halide-free synthesis of cyclic carbonates from epoxides and carbon dioxide. Deuterated and enantiomerically-pure epoxides were used to study the reaction pathway. Based on the experimental and theoretical results, a catalytic cycle is proposed.
- Castro-Osma, José A.,North, Michael,Offermans, Willem K.,Leitner, Walter,Müller, Thomas E.
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p. 791 - 794
(2016/05/02)
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- Aluminum(salen) complexes as catalysts for the kinetic resolution of terminal epoxides via CO2 coupling
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The development of inexpensive and sustainable aluminum(salen) complexes as catalysts for the kinetic resolution of terminal epoxides is described. The kinetic resolution is carried out under mild conditions (0-25 °C and 1 bar of CO2 pressure) in the presence of tetrabutylammonium bromide as co-catalyst in the absence of solvent. The relative rate of reaction of the two epoxide enantiomers (krel) is substrate dependent, and the highest krel obtained was 15.4, using N-(2,3-epoxypropyl)diphenylamine as substrate.
- North, Michael,Quek, Sophie C. Z.,Pridmore, Natalie E.,Whitwood, Adrian C.,Wu, Xiao
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p. 3398 - 3402
(2015/06/16)
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- Quaternary ammonium hydroxide as a metal-free and halogen-free catalyst for the synthesis of cyclic carbonates from epoxides and carbon dioxide
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Tetrabutylammonium hydroxide (TBAH) and other quaternary ammonium hydroxides catalyzed the cycloaddition of CO2 to epoxides under solvent-free conditions to give cyclic carbonates. When TBAH was exposed to CO2, TBAH was converted into tetrabutylammonium bicarbonate (TBABC), which was a catalytically active species. A D-labeled epoxide and an optically active epoxide were used to study the reaction mechanism, which invoked three plausible pathways. Among them, path A seemed to be predominant; the bicarbonate ion of TBABC attacks the less hindered C atom of the epoxide to generate a ring-opened alkoxide intermediate, which adds to CO2 to give a carbonate ion, and the subsequent cyclization yields a cyclic carbonate. Density functional theory (DFT) calculations successfully delineated the potential energy profile for each reaction pathway, among which path A was the lowest-energy pathway in accordance with the experimental results. The tetrabutylammonium (TBA) cation carries the positive charges on the H atoms, but not on the central N atom, and the positively charged H atoms close to the central N atom form an anion-binding site capable of stabilizing various anionic transition states and intermediates.
- Ema, Tadashi,Fukuhara, Kazuki,Sakai, Takashi,Ohbo, Masaki,Bai, Fu-Quan,Hasegawa, Jun-Ya
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p. 2314 - 2321
(2015/04/14)
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- Metal-Organic Polymers Containing Discrete Single-Walled Nanotube as a Heterogeneous Catalyst for the Cycloaddition of Carbon Dioxide to Epoxides
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The cycloaddition of carbon dioxide to epoxides to produce cyclic carbonates is quite promising and does not result in any side products. A discrete single-walled metal-organic nanotube was synthesized by incorporating a tetraphenyl-ethylene moiety as the four-point connected node. The assembled complex has a large cross-section, with an exterior wall diameter of 3.6 nm and an interior channel diameter of 2.1 nm. It features excellent activity toward the cycloaddition of carbon dioxide, with a turnover number of 17,500 per mole of catalyst and an initial turnover frequency as high as 1000 per mole of catalyst per hour. Only minimal decreases in the catalytic activity were observed after 70 h under identical reaction conditions, and a total turnover number as high as 35,000 was achieved. A simple comparison of relative porous MOFs suggested that the cross-section of the channels is an important factor influencing the transport of the substrates and products through the channel.
- Zhou, Zhen,He, Cheng,Xiu, Jinghai,Yang, Lu,Duan, Chunying
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supporting information
p. 15066 - 15069
(2015/12/20)
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- CO2 Adducts of Phosphorus Ylides: Highly Active Organocatalysts for Carbon Dioxide Transformation
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A series of phosphorus ylide (P-ylide) CO2 adducts were synthesized and first used as organocatalysts for CO2 transformation. Detailed studies on the cycloaddition reaction of CO2 with terminal epoxides show that P-ylide CO2 adducts are efficient metal-free and halogen-free organocatalysts to mediate this reaction under ambient conditions (25 °C, 1 atm of CO2). More importantly, the reactions proceeded with a broad scope, high efficiency, and good functional group tolerance and the corresponding cyclic carbonate products were obtained in good to excellent yields (46-99%). Meanwhile, the kinetic study by in situ FTIR methods suggested an intermolecular cooperation effect for effectively accelerating the ring opening of terminal epoxides. Furthermore, from an investigation of the catalytic diversity of P-ylide CO2 adducts, CO2 also could be converted to functionalized cyclic α-alkylidene carbonates, oxazolidinone, and N-methylated and N-formylated amines by organocatalytic reactions.
- Zhou, Hui,Wang, Guo-Xu,Zhang, Wen-Zhen,Lu, Xiao-Bing
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p. 6773 - 6779
(2015/11/18)
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- Bifunctional aluminum catalyst for CO2 fixation: Regioselective ring opening of three-membered heterocyclic compounds
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Regioselective ring opening of three-membered heterocyclic compounds (epoxides or N-substituted aziridines) at various temperatures was observed in coupling reactions with CO2 by the use of an aluminum - salen catalyst in conjunction with intramolecular quaternary ammonium salts as cocatalysts, affording the corresponding five-membered cyclic products with complete configuration retention at the methine carbon. Notably, this bifunctional aluminum-based catalyst exhibited nearly 100% regioselectivity for the ring opening at the methylene C-O bond for various terminal epoxides. This was true for those bearing an electron-withdrawing group, such as styrene oxide or epichlorohydrin, thereby affording the synthesis of various enantiopure cyclic carbonates that have previously been obtained only rarely by other methods. An intramolecular cooperative catalysis is suggested to contribute to the high activity and excellent stereochemistry control observed. Surprisingly, the highly selective ring opening at the methine carbon of N-substituted aziridines was found in the coupling with CO2, predominantly giving 5-substituted oxazolininones with retention of configuration as a result of double inversion at the methine carbon. (Chemical Equation Presented).
- Ren, Wei-Min,Liu, Ye,Lu, Xiao-Bing
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p. 9771 - 9777
(2015/02/19)
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- Synthesis of cyclic carbonates from CO2 and epoxides catalyzed by low loadings of benzyl bromide/DMF at ambient pressure
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An efficient, metal-free catalytic system for the conversion of CO2 and epoxides to cyclic carbonates under mild conditions with good-to-excellent yields (57-99%) was developed. A possible reaction mechanism involving the electrophilic activation of epoxides by benzyl cations and nucleophilic activation of CO2 by DMF is proposed. This journal is
- Wang, Lin,Lin, Li,Zhang, Guangyou,Kodama, Koichi,Yasutake, Mikio,Hirose, Takuji
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supporting information
p. 14813 - 14816
(2015/02/19)
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- Silanediol-catalyzed carbon dioxide fixation
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Carbon dioxide is an abundant and renewable C1 source. However, mild transformations with carbon dioxide at atmospheric pressure are difficult to accomplish. Silanediols have been discovered to operate as effective hydrogen-bond donor organocat
- Hardman-Baldwin, Andrea M.,Mattson, Anita E.
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p. 3275 - 3278
(2015/02/05)
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- Metal-free synthesis of cyclic and acyclic carbonates from CO2 and alcohols
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Diverse cyclic and acyclic carbonates such as ethylene carbonate, propylene carbonate, glycerol carbonate, and dimethyl carbonate were synthesized in moderate to good yields by the direct coupling of the corresponding alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5. 4.0]undec-7-ene, 1-butyl-3-methylimidazolium hexafluorophosphate, and dibromomethane was probed by 18O-labeling experiments and chiral alcohol experiments.
- Lim, Yu Na,Lee, Chan,Jang, Hye-Young
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p. 1823 - 1826
(2014/04/03)
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- Metal-Free Synthesis of Cyclic and Acyclic Carbonates from CO2 and Alcohols
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Diverse cyclic and acyclic carbonates such as ethylene carbonate, propylene carbonate, glycerol carbonate, and dimethyl carbonate were synthesized in moderate to good yields by the direct coupling of the corresponding alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1-butyl-3-methylimidazolium hexafluorophosphate, and dibromomethane was probed by 18O-labeling experiments and chiral alcohol experiments. Diverse cyclic and acyclic carbonates were synthesized in moderate to good yields by the direct coupling of alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was probed by an 18O-labeling experiment and a chiral alcohol experiment.
- Lim, Yu Na,Lee, Chan,Jang, Hye-Young
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p. 1823 - 1826
(2015/10/05)
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- 'Ring-expansion addition' of epoxides using applied potential: An investigation of catalysts for atmospheric pressure carbon dioxide utilization
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Interest in the use of CO2 as a feedstock for preparation of value-added compounds has dramatically increased over the past decade. We herein investigate the insertion of atmospheric pressure carbon dioxide under electrosynthetic conditions into epoxides. The initial investigations involved the use of either a nickel or copper based catalyst, however, upon further optimisation and careful selection of electrode materials we found that these catalysts were not required for efficient carbon dioxide insertion to occur.
- Buckley, Benjamin R.,Patel, Anish P.,Wijayantha, K. G. Upul
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p. 58581 - 58590
(2015/02/19)
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- METHODS AND SYSTEMS FOR THE FORMATION OF CYCLIC CARBONATES
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Described herein are inventive methods for synthesis of cyclic carbonates from C02 and epoxide. In some embodiments, the methods are carried out in the presence of a catalyst comprising an electrophilic halogen. In some embodiments, the methods are carried out in a flow reactor.
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Page/Page column 30; 35
(2013/12/03)
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- Bromine-catalyzed conversion of CO2 and epoxides to cyclic carbonates under continuous flow conditions
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A continuous method for the formation of cyclic carbonates from epoxides and carbon dioxide (CO2) is described. The catalysts used are inexpensive and effective in converting the reagents to the products in a residence time (tR) of 30 min. The cyclic carbonate products are obtained in good to excellent yield (51-92%). On the basis of a series of kinetics experiments, we propose a reaction mechanism involving epoxide activation by electrophilic bromine and CO2 activation by an amide.
- Kozak, Jennifer A.,Wu, Jie,Su, Xiao,Simeon, Fritz,Hatton, T. Alan,Jamison, Timothy F.
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supporting information
p. 18497 - 18501
(2014/01/06)
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- A bifunctional catalyst for carbon dioxide fixation: Cooperative double activation of epoxides for the synthesis of cyclic carbonates
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We have developed a very active bifunctional porphyrin catalyst showing a high turnover number (TON = 103000) for the synthesis of cyclic carbonates from CO2 and epoxides under solvent-free conditions.
- Ema, Tadashi,Miyazaki, Yuki,Koyama, Shohei,Yano, Yuya,Sakai, Takashi
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supporting information; experimental part
p. 4489 - 4491
(2012/05/20)
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