- Highly active electrophile-nucleophile catalyst system for the cycloaddition of CO2 to epoxides at ambient temperature
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The cycloaddition of CO2 to epoxides proceeds effectively under extremely mild temperatures and pressures by using a bifunctional catalyst system of tetradentate Schiff-base aluminum complexes (SalenAlX) as electrophile in conjunction with polyether-KY complexes as nucleophile. The steric factor of the substituent groups on the aromatic rings of SalenAlX and the nucleophilicity and leaving ability of the anion Y-1 of polyether-KY complexes all have great effects on the activity of the bifunctional catalyst system. The reaction of CO2 with (S)-propylene oxide in the presence of the SalenAlEt/18-crown-6-KI catalyst system gives (S)-propylene carbonate in > 99 % ee with retention of stereochemistry.
- Lu, Xiao-Bing,Zhang, Ying-Ju,Jin, Kun,Luo, Li-Mei,Wang, Hui
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Read Online
- 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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- 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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- A (S)- propylene carbonate synthesis method (by machine translation)
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The present invention provides a (S)- propylene carbonate synthesis method, comprises a batch charging, temperature reaction, cooling, decompression desolution of the reaction. The invention preparation of (S)- propylene carbonate, yield is 97%; the invention preparation of (S)- propylene carbonate, the specific optical rotation is - 2 - - 3; chemical pure content ≥ 99.8%; optical pure content ≥ 99.4%; isomer content ≤ 0.6%; water content ≤ 0.1%; the appearance is a colorless clear transparent liquid; from feeding to prepare crude product, the reaction time is 25 hours. (by machine translation)
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Paragraph 0017-0026
(2019/03/08)
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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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- 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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- 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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supporting information
p. 3908 - 3915
(2017/08/22)
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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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- 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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- Lewis acid-base bifunctional aluminum-salen catalysts: synthesis of cyclic carbonates from carbon dioxide and epoxides
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Two Lewis acid-base bifunctional monometallic aluminum-salen complexes were prepared based on a new type of salen ligand with two N-methylhomopiperazine moieties at the 3,3′-position. The Al(salen) complexes proved to be efficient and recyclable homogeneous catalysts towards the organic solvent-free synthesis of cyclic carbonates from epoxides and CO2 in the absence of a co-catalyst, in which >90% yield of cyclic carbonate could be obtained under relatively mild conditions. The catalysts can be easily recovered and reused five times without significant loss of activity and selectivity. Furthermore, the Lewis acid-base cooperative activation mechanism by the bifunctional Al(salen) complexes was proposed according to experimental data.
- Ren, Yanwei,Jiang, Ou,Zeng, Hang,Mao, Qiuping,Jiang, Huanfeng
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p. 3243 - 3249
(2016/01/16)
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- Mechanism and origins of enantioselectivity for [BMIM]Cl ionic liquids and ZnCl2 co-catalyzed coupling reaction of CO2 with epoxides
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Aiming at gaining more insight into the high catalytic activity of ZnCl2/[BMIM]Cl co-catalysts and elucidating the origination about the product enantioselectivity for the coupling reaction of CO2 with epoxides, a mechanistic study has been conducted by performing density functional theory calculations. The calculated results indicate a new stable complex [BMIM]ZnCl3 is probably formed via the dissociation of the in situ generated [BMIM]2ZnCl4 complex in the reaction system. This complex combined with another Cl- jointly assists the break of CO bond of propylene oxide (PO), which is the rate-determining step for the coupling reaction, and the corresponding barrier (28.0 kcal mol -1) is effectively lowered in comparison with the reaction promoted only by ZnCl2 (65.9 kcal mol-1) or [BMIM]Cl (33.1 kcal mol-1). [BMIM]+ takes part in the reaction by directly or indirectly stabilizing the intermediates and transition states via hydrogen bonding interaction with O of PO or Cl- in the reaction system. The observed product enantioselectivity probably originates from the formation of an interesting intermediate which provides nearly equal opportunities for inserted CO2 to attack the chiral carbon atom of PO on both sides and hence facilitates the formation of both R-product and S-product.
- Wang, Fang,Xu, Chuanzhi,Li, Zhen,Xia, Chungu,Chen, Jing
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p. 133 - 140
(2014/03/21)
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- A chiral mixed metal-organic framework based on a Ni(saldpen) metalloligand: Synthesis, characterization and catalytic performances
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A three-dimensional (3D) chiral mixed metal-organic framework [Cd 4Cl(Ni-L)3(Ni-HL)(H2O)6(DMF)] ·4DMF (CMOF 1) based on a new enantiopure dicarboxyl-functionalized Ni(saldpen) metalloligand Ni-H2L and a novel tetranuclear cadmium cluster [Cd4Cl(CO2)7(CO2H)] has been synthesized and characterized by elemental analyses, IR and UV-vis spectra, thermogravimetric analysis, nitrogen and carbon dioxide adsorption, powder and single-crystal X-ray diffractions. Each tetranuclear-cadmium cluster in 1 is linked by eight Ni-L ligands, and each Ni-L ligand is linked by two tetranuclear-cadmium clusters to generate a 3D framework with 1D open channels (~1.1 × 0.9 nm2) along the b-axis. Based on its good stability, permanent porosity, Lewis acid sites and moderate uptake for CO 2, 1 can be used as a self-supported heterogeneous catalyst for the synthesis of optically active propylene carbonate by asymmetric cycloaddition of CO2 with racemic propylene oxide under relatively mild conditions. The Royal Society of Chemistry 2013.
- Ren, Yanwei,Cheng, Xiaofei,Yang, Shaorong,Qi, Chaorong,Jiang, Huanfeng,Mao, Qiuping
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supporting information
p. 9930 - 9937
(2013/08/23)
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- Asymmetric cycloaddition of CO2 and an epoxide using recyclable bifunctional polymeric Co(iii) salen complexes under mild conditions
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Bifunctional polymeric Co(iii) salen complexes 1a-g derived from (1R,2R)-(-)-1,2-diaminocyclohexane and a triazine-piperazine core were synthesized and screened for the asymmetric cycloaddition reaction of CO 2 and an epoxide under mild conditions. A moderate Krel value of 11.2 for the product propylene carbonate (ee = 74%) was obtained with catalyst 1e which does not require any external base as the co-catalyst. The polymeric Co(iii)-CCl3COO (1e) was efficiently recycled 10 times without any significant loss in activity under the present reaction conditions.
- Roy, Tamal,Kureshy, Rukhsana I.,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
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p. 2661 - 2667
(2013/09/24)
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- Chiral metal-containing ionic liquid: Synthesis and applications in the enantioselective cycloaddition of carbon dioxide to epoxides
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A series of novel chiral metal-containing ionic liquids (CMILs) consisting of the cation of crown ether-chelated potassium/sodium and the anion of chiral amino acids were designed and synthesized. These new CMILs were used to catalyze the enantioselective cycloaddition of epoxides and carbon dioxide incorporating with the salenCo(OOCCCl3) to generate corresponding chiral cyclic carbonates under mild conditions. These new catalysts can be recycled at least five times without significant loss of activity and enantioselectivity.
- Song, Yingying,Jin, Qianru,Zhang, Suling,Jing, Huanwang,Zhu, Qianqian
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scheme or table
p. 1044 - 1050
(2012/04/04)
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- A homogeneous catalyst for reduction of optically active esters to the corresponding chiral alcohols without loss of optical purities
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A ruthenium complex was found to catalyze the hydrogen reduction of esters under mild and neutral conditions. A variety of optically active esters can be reduced to the corresponding alcohols in excellent yield without loss of their optical purity or causing undesirable side reactions. Hydrogen reduction needs such simple operations - reaction, concentration, and purification - that the violent quench step and extraction step, which accompany conventional sodium borohydride or lithium aluminum hydride reduction, can be omitted.
- Kuriyama, Wataru,Ino, Yasunori,Ogata, Osamu,Sayo, Noboru,Saito, Takao
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supporting information; experimental part
p. 92 - 96
(2010/06/17)
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- Catalytic Asymmetric Cycloaddition of Carbon Dioxide and Propylene Oxide Using Novel Chiral Polymers of BINOL-SalenCobalt(III) Salts
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Four new chiral polymers of BINOLSalen-cobalt(III) salt complexes have been designed, synthesized and applied to the direct fabrication of chiral propylene carbonate from racemic propylene oxide. The (R/S)-polymer catalyst 2 and (S/R)-polymer catalyst 4 exhibit better enantioselectivity than the (R/R)-polymer catalyst 1 and the (S/S)-polymer catalyst 3 and have been recovered and reused more than ten times without loss of activity and enantioselectivity.
- Yan, Peng,Jing, Huanwang
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experimental part
p. 1325 - 1332
(2009/12/24)
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- Chiral ionic liquids improved the asymmetric cycloaddition of CO 2 to epoxides
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The new catalyst system of chiral SalenCo(OAc)/chiral ionic liquid was developed to catalyze the asymmetric cycloaddition reaction of CO2 and epoxides yielding the chiral cyclic carbonates. The synergistic effect between them is discussed.
- Zhang, Suling,Huang, Yongzhong,Jing, Huanwang,Yao, Weixuan,Yan, Peng
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supporting information; experimental part
p. 935 - 938
(2010/04/23)
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- Chiral catalysts for the asymmetric cycloaddition of carbon dioxide with epoxides
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Several chiral BINADCo(III)X (BINAD = Bis(1,1′-2-hydroxy-2′-alkoxy-3-naphthylidene)-1,2-cyclohexanediamine, X = OAc, CF3CO2, CCl3CO2, OTs, p-NO2PhCO2) complexes were synthesized and used to
- Jin, Lili,Huang, Yongzhong,Jing, Huanwang,Chang, Tao,Yan, Peng
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p. 1947 - 1953
(2008/12/22)
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- Intramolecularly two-centered cooperation catalysis for the synthesis of cyclic carbonates from CO2 and epoxides
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A catalyst system containing an electrophilic center and a sterically hindered nucleophilic center in one molecule was applied to the cycloaddition reaction of CO2 and epoxides. This intramolecularly two-centered cooperation catalyst showed activity even at a high [epoxide]/[catalyst] ratio up to 50 000 under mild conditions such as solvent-free, ambient temperature, and low CO2 pressure. The reaction of CO2 with (S)-propylene oxide at 80 °C in the presence of the bifunctional catalyst gives (S)-propylene carbonate in 96% ee with retention of stereochemistry.
- Zhang, Xiang,Jia, Yin-Bao,Lu, Xiao-Bing,Li, Bo,Wang, Hui,Sun, Li-Cheng
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body text
p. 6589 - 6592
(2009/04/06)
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- Efficient catalytic synthesis of optically active cyclic carbonates via coupling reaction of epoxides and carbon dioxide
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Chiral Co(salen) complexes bearing the Lewis acid of group 13 can efficiently catalyze the reactions of carbon dioxide with epoxides in the presence of catalytic amounts of alkali metal salts, quaternary ammonium halide or ionic liquids. They exhibited ex
- Chen, Shu-Wei,Kawthekar, Rahul B.,Kim, Geon-Joong
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p. 297 - 300
(2007/10/03)
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- Catalytic asymmetric addition of carbon dioxide to propylene oxide with unprecedented enantioselectivity
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New chiral catalyst systems were developed for the reaction of carbon dioxide with propylene oxide (PO) at atmospheric pressure to generate enantiomerically enriched propylene carbonate (PC). The best selectivity was achieved with a CoIII(salen)-trifluoroacetyl complex and bis-(triphenylphosphoranylidene)ammonium fluoride (PPN+F-) as catalysts, affording PC in 40% yield and 83% ee (selectivity factor = 19). In addition, PC was prepared for the first time by kinetic resolution of PO with tetrabutylammonium methyl carbonate (TBAMC, nBu4N +-OOCOMe). With TBAMC as "activated CO2", up to 71% ee was obtained.
- Berkessel, Albrecht,Brandenburg, Marc
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p. 4401 - 4404
(2007/10/03)
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- Asymmetric Catalysis with CO2: Direct Synthesis of Optically Active Propylene Carbonate from Racemic Epoxides
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This communication describes a convenient route to optically active propylene carbonate by a catalytic kinetic resolution process resulting from the coupling reaction of CO2 and racemic epoxides using simple chiral SalenCo(III)/quaternary ammonium halide catalyst systems. Copyright
- Lu, Xiao-Bing,Liang, Bin,Zhang, Yin-Ju,Tian, Yu-Zeng,Wang, Yi-Ming,Bai, Chen-Xi,Wang, Hui,Zhang, Rong
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p. 3732 - 3733
(2007/10/03)
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- Chiral (salen)CoIII catalyst for the synthesis of cyclic carbonates
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A catalyst system comprised of a CoIII(salen) complex and aLewis base is investigated for the reaction of CO2 and a variety of epoxides to form cyclic carbonates. Application of this catalyst system in the kinetic resolution of propylene oxide is also discussed.
- Paddock, Robert L.,Nguyen, Sonbinh T.
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p. 1622 - 1623
(2007/10/03)
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- Preparation of Cyclic Carbonates from Oxiranes and Carbon Dioxide in the Presence of Bifunctional Catalysts
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Mixtures of metal halides and alkylammonium iodides catalyze the synthesis of cyclic carbonates 2 from oxiranes and carbon dioxide at room temperature and atmospheric pressure.The chemoselective reaction proceeds smoothly with mono-substituted oxiranes while 1,2-disubstituted substrates are inert.By the use of chiral oxiranes the reaction opens a simple access to chiral carbonates like (R)- and (S)-4-(chloromethyl)-1,3-dioxolan-2-one (2c).Insertion of carbon dioxide into the C-O bond occurs with retention of configuration and with optical yields of 73 - 98 percent.
- Kisch, Horst,Millini, Roberto,Wang, Ing-Jing
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p. 1090 - 1094
(2007/10/02)
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