- Efficient Ionic-Liquid-Promoted Chemical Fixation of CO2 into Α-Alkylidene Cyclic Carbonates
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The efficient conversion of CO2 into value-added chemicals under metal-free conditions is of significant importance from the viewpoint of sustainable chemistry. In this work, ionic liquids (ILs) with different properties were used to promote th
- Qiu, Jikuan,Zhao, Yuling,Li, Zhiyong,Wang, Huiyong,Fan, Maohong,Wang, Jianji
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- Copper-Promoted Coupling of Carbon Dioxide and Propargylic Alcohols: Expansion of Substrate Scope and Trapping of Vinyl Copper Intermediate
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We have successfully demonstrated that in the presence of N,N-diisopropylethylamine, copper iodide could efficiently catalyze the coupling of internal propargylic alcohols with carbon dioxide to afford the corresponding α-alkylidene cyclic carbonates in m
- Ouyang, Lu,Tang, Xiaodong,He, Haitao,Qi, Chaorong,Xiong, Wenfang,Ren, Yanwei,Jiang, Huanfeng
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- Stereoselective preparation of Z-trisubstituted alkylidene cyclic carbonates via palladium-catalyzed carbon - carbon bond formation
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Alkylidene cyclic carbonates bearing a Z-trisubstituted exocyclic double bond have been stereoselectively prepared in good yields for the first time from methylene cyclic carbonates, resistant to the classical Heck reaction, on treatment with aryl iodides, CF3CO2Ag and palladium catalyst, under conditions which tolerate (sp2)C-Br bonds. (C) 2000 Elsevier Science Ltd.
- Toullec, Patrick,Carbayo Martin, Aranzazu,Gio-Batta, Monica,Bruneau, Christian,Dixneuf, Pierre H.
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- Palladium-Catalyzed Arylcarboxylation of Propargylic Alcohols with CO2 and Aryl Halides: Access to Functionalized α-Alkylidene Cyclic Carbonates
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A palladium-catalyzed, three-component reaction between propargylic alcohols, CO2, and aryl halides was developed whereby a sequential carboxylation, trans-oxopalladation of the C≡C bond by an ArPdX species, and a reductive elimination procedur
- Sun, Song,Wang, Bingbing,Gu, Ning,Yu, Jin-Tao,Cheng, Jiang
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- Silver-catalyzed incorporation of carbon dioxide into propargylic alcohols
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The combined use of a catalytic amount of silver acetate and a stoichiometric amount of DBU efficiently catalyzed the incorporation of CO 2 under mild reaction conditions into a wide range of propargylic alcohols bearing a terminal or an intern
- Yamada, Wataru,Sugawara, Yudai,Hau, Man Cheng,Ikeno, Taketo,Yamada, Tohru
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- Stereoselective formation of α-alkylidene cyclic carbonates via carboxylative cyclization of propargyl alcohols in supercritical carbon dioxide
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Carboxylative cyclization of propargyl alcohols in supercritical carbon dioxide (scCO2) containing P(n-C4H9) 3 as a catalyst proceeded smoothly to give α-alkylidene-1,3- dioxolan-2-ones. Internal propargyl alcohols afforded Z-alkylidene cyclic carbonates exclusively. CO2 incorporation was markedly promoted under supercritical conditions, possibly due to the facile formation of a putative P(n-C4H9)3-CO2 adduct as a key intermediate.
- Kayaki, Yoshihito,Yamamoto, Masafumi,Ikariya, Takao
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- Isolable CO2 Adducts of Polarized Alkenes: High Thermal Stability and Catalytic Activity for CO2 Chemical Transformation
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Various CO2 adducts of tetra-hydropyrimidin-2-ylidene (THPE) derived from the commercially available 1, 5-diazabicyclo[4.3.0]non-5-ene (DBN) were firstly synthesized. X-ray single crystal analysis revealed the bent geometry of the binding CO2 having an O?C?O angle of 127.50~129.51° for THPE?CO2 adducts. In situ FTIR experiments demonstrated that THPE?CO2 adducts had unprecedented thermal stability in DMSO, even at 100 °C without decomposition. It was found that the THPE?CO2 adducts were highly active in catalyzing the carboxylative cyclization of CO2 with propargylic alcohols under mild conditions, significantly higher than the previously reported organocatalysts. Various internal and terminal functionalized propargylic alcohols were tolerated in these processes to afford the corresponding α-alkylidene cyclic carbonates in moderate to good yields with complete (Z)-stereoselectivity. Isotope labeling, in combination with in-situ FTIR and stoichiometric experiments, reveal that the catalytic reaction tends to proceed via the THPE?CO2-mediated basic ionic pair mechanism. (Figure presented.).
- Zhou, Hui,Zhang, Rui,Lu, Xiao-Bing
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p. 326 - 334
(2019/01/04)
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- Alkoxide-functionalized imidazolium betaines for CO2 activation and catalytic transformation
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Alkoxide-functionalized imidazolium betaines (AFIBs), including an alkoxide anion and an imidazolium cation, were synthesized by treating potassium tert-butoxide with 1-(2-hydroxyethyl)-2,3-disubstituted imidazolium bromide. The novel betaines were able to quickly capture CO2, affording carboxylate zwitterions (AFIB-CO2 adducts). In the presence of adventitious water, the transformation of the AFIB-CO2 adducts into the corresponding bicarbonate salts was observed by 1H and 13C NMR spectroscopy. The structures of the AFIB bicarbonate salts were solved using single crystal X-ray crystallography. Furthermore, the dithiocarboxylate zwitterions (AFIB-CS2 adducts), which are more stable to moisture in comparison with their CO2 adducts, were prepared by reacting CS2 with the corresponding betaines. X-Ray single crystal analysis revealed the bent geometry of the binding CS2 in the dithiocarboxylate zwitterions with a S-C-S angle of 126.6-126.9°, which indirectly confirms the structures of the AFIB-CO2 adducts in hand. These AFIB-CO2 adducts were found to function as organocatalysts for the coupling reaction of propargylic alcohols with CO 2 for selectively producing valuable cyclic carbonates under mild and solvent-free reaction conditions. the Partner Organisations 2014.
- Wang, Yan-Bo,Sun, Dong-Sheng,Zhou, Hui,Zhang, Wen-Zhen,Lu, Xiao-Bing
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p. 2266 - 2272
(2014/04/17)
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- Fast CO2 sequestration, activation, and catalytic transformation using N -heterocyclic olefins
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N-Heterocyclic Olefin (NHO) with high electronegativity at the terminal carbon atom was found to show a strong tendency for CO2 sequestration, affording a CO2 adduct (NHO-CO2). X-ray single crystal analysis revealed the bent geometry of the binding CO2 in the NHO-CO2 adducts with an O-C-O angle of 127.7-129.9, dependent on the substitute groups of N-heterocyclic ring. The length of the C carboxylate-CNHO bond is in the range of 1.55-1.57 A, significantly longer than that of the Ccarboxylate-C NHC bond (1.52-1.53 A) of the previously reported NHC-CO 2 adducts. The FTIR study by monitoring the ν(CO2) region of transmittance change demonstrated that the decarboxylation of NHO-CO2 adducts is easier than that of the corresponding NHC-CO 2 adducts. Notably, the NHO-CO2 adducts were found to be highly active in catalyzing the carboxylative cyclization of CO2 and propargylic alcohols at mild conditions (even at ambient temperature and 0.1 MPa CO2 pressure), selectively giving α-alkylidene cyclic carbonates in good yields. The catalytic activity is about 10-200 times that of the corresponding NHC-CO2 adducts at the same conditions. Two reaction paths regarding the hydrogen at the alkenyl position of cyclic carbonates coming from substrate (path A) or both substrate and catalyst (path B) were proposed on the basis of deuterium labeling experiments. The high activity of NHO-CO2 adduct was tentatively ascribed to its low stability for easily releasing the CO2 moiety and/or the desired product, a possible rate-limiting step in the catalytic cycle.
- Wang, Yan-Bo,Wang, Yi-Ming,Zhang, Wen-Zhen,Lu, Xiao-Bing
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supporting information
p. 11996 - 12003
(2013/09/02)
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- A bifunctional tungstate catalyst for chemical fixation of CO2 at atmospheric pressure
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No pressure: A simple monomeric tungstate, [WO4]2-, serves as a highly efficient homogeneous catalyst for various transformations of CO2 at atmospheric pressure. The tungsten-oxo moiety activates CO2 and the substrate simultaneously. The catalyst system is high yielding and applicable to a wide range of substrates such as amines (see scheme), 2-aminobenzonitriles, and propargylic alcohols. Copyright
- Kimura, Toshihiro,Kamata, Keigo,Mizuno, Noritaka
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supporting information; experimental part
p. 6700 - 6703
(2012/08/28)
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- Silver-catalyzed carbon dioxide incorporation and rearrangement on propargylic derivatives
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A silver/DBU catalyst system was developed for the effective synthesis of cyclic carbonate and oxazolidinone from the reaction of CO2 with propargylic alcohols and propargylic amines, respectively, in high yields under mild conditions. It was f
- Kikuchi, Satoshi,Yoshida, Shunsuke,Sugawara, Yuudai,Yamada, Wataru,Cheng, Hau-Man,Sekine, Kohei,Iwakura, Izumi,Ikeno, Taketo,Yamada, Tohru
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experimental part
p. 698 - 717
(2011/09/14)
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- Effective guanidine-catalyzed synthesis of carbonate and carbamate derivatives from propargyl alcohols in supercritical carbon dioxide
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The reactions of propargyl alcohols with carbon dioxide in supercritical carbon dioxide or in acetonitrile with gaseous carbon dioxide in the presence of organic bases as catalysts have been examined. Bicyclic guanidines are effective catalysts for the formation of α-methylene cyclic carbonates under mild reaction conditions. Oxoalkyl carbonates, oxoalkyl carbamates or α-methyleneoxazolidinones are obtained in high yields and good selectivities in one-step starting from propargyl alcohols and an external nucleophile (alcohols or amines) using bicyclic guanidines as catalysts in supercritical carbon dioxide. Propargylic diols under the same reaction conditions underwent a rearrangement process instead of carbon dioxide insertion whereas in the presence of an external nucleophile the formation of oxocarbonates, oxocarbamates or cyclic carbamates was achieved in satisfactory yields.
- Ca', Nicola Della,Gabriele, Bartolo,Ruffolo, Giuseppe,Veltri, Lucia,Zanetta, Tito,Costa, Mirco
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scheme or table
p. 133 - 146
(2011/04/18)
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