- A new, facile method to prepare hybrid calcium poly(styrene-phenylvinylphosphonate)-phosphate materials for a superior performance catalyst support
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A simple and facile route is developed to synthesize a new type of calcium poly(styrene-phenylvinylphosphosphonate)-phosphate (CaPS-PVPA). Structure analysis reveals that CaPS-PVPA is a layered crystalline mesoporous material and could have potential appl
- Huang, Jing,Tang, Mei,Li, Chang Ming
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- Biomimetic non-heme iron-catalyzed epoxidation of challenging terminal alkenes using aqueous H2O2 as an environmentally friendly oxidant
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Catalysis mediated by iron complexes is emerging as an eco-friendly and inexpensive option in comparison to traditional metal catalysis. The epoxidation of alkenes constitutes an attractive application of iron(III) catalysis, in which terminal olefins are challenging substrates. Herein, we describe our study on the design of biomimetic non-heme ligands for the in situ generation of iron(III) complexes and their evaluation as potential catalysts in epoxidation of terminal olefins. Since it is well-known that active sites of oxidases might involve imidazole fragment of histidine, various simple imidazole derivatives (seven compounds) were initially evaluated in order to find the best reaction conditions and to develop, subsequently, more elaborated amino acid-derived peptide-like chiral ligands (10 derivatives) for enantioselective epoxidations.
- Fingerhut, Anja,Vargas-Caporali, Jorge,Leyva-Ramírez, Marco Antonio,Juaristi, Eusebio,Tsogoeva, Svetlana B.
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- Stable chiral salen Mn(III) complexes with built-in phase-transfer capability for the asymmetric epoxidation of unfunctionalized olefins using NaOCl as an oxidant
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A series of novel chiral salen Mn(III) complexes with inherent phase-transfer capability were prepared by covalent linkage of the limidazolium IL moieties containing various PEG chains with chiral salen ligand at two sides of 5,5′-position. Technologies of characterization well suggested the presence of polyether chain, the IL linker, and the intact active sites in the complexes. The amphipathic nature of the PEG chain allowed the PEG-based catalysts to undergo built-in phase transfer, which in turn increased the reaction rates in water/organic biphasic systems. Enantioselective epoxidation of styrene, α-methylstyrene, indene, 1,2-dihydronaphthalene, 6-cyano-2,2-dimethylchromene, and 6-nitro-2,2-dimethylchromene catalyzed by the complexes with NaOCl gave >99% conversions within 60 min. The enantiomeric excess (ee) for the epoxides was in the range of 68-93%, except for styrene (ee, 35%) and α-methylstyrene (ee, 42%). Furthermore, the PEG-based complexes were stable and could be separated from the reaction mixture by control of the solvent.
- Luo, Rongchang,Tan, Rong,Peng, Zhigang,Zheng, Weiguo,Kong, Yu,Yin, Donghong
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- Synthesis and catalytic reactivity of D4-symmetric dinorbornabenzene-derived metallotetraarylporphyrins
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The condensation of the resolved C2-symmetric benzaldehyde, 1,2,3,4,5,6,7,8-octahydro-1:4,5: 8-dimethanoanthracene-9-carboxyaldehyde, with pyrrole produced the first chiral tetraarylporphyrin 1 exhibiting D4-symmetry. The resolved benzaldehyde was synthesized in seven steps from p-benzoquinone and cyclopentadiene and included a resolution via diastereomeric ketals. A manganese chloride complex of porphyrin 1 was used as a catalyst for the asymmetric epoxidation of aromatic substituted alkenes in the presence of excess sodium hypochlorite in up to 7,200 turnovers and up to 76% e.e and >90% yield.
- Halterman, Ronald L.,Jan, Shyi-Tai,Nimmons, Heather L.,Standlee, David J.,Khan, Masood A.
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- An effective strategy for creating asymmetric MOFs for chirality induction: A chiral Zr-based MOF for enantioselective epoxidation
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Recently the construction of chiral MOFs (CMOFs) has been very challenging and complex. For the first time, we synthesized a chiral Zr-based MOF with l-tartaric acid by solvent-assisted ligand incorporation (SALI). We show that a CMOF can be postsynthetically generated by a simple method: incorporating chiral carboxylic groups on the achiral NU-1000. The post-synthesized chiral NU-1000 was used as an asymmetric support for producing a chiral catalyst with molybdenum catalytic active centers as Lewis acid sites. Enantioselective epoxidation of various prochiral alkens to epoxids by using [C-NU-1000-Mo] is comparable to that using other asymmetric homogeneous and heterogeneous catalysts, along with high enantiomeric excess and selectivity to epoxide (up to 100%). The CMOF could be reused in the styrene oxidation after five cycles without substantial deterioration in the CMOF crystallinity or catalytic performance.
- Berijani, Kayhaneh,Morsali, Ali,Hupp, Joseph T.
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- Iridium-catalyzed alternative of the Meinwald rearrangement
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A novel and easy to handle procedure for the regioselective rearrangement of epoxides has been developed, based on an iridium catalyst.
- Karamé, Iyad,Tommasino, M. Lorraine,Lemaire, Marc
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- Enhanced enantioselective oxidation of olefins catalyzed by Mn-porphyrin immobilized on graphene oxide
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An efficient enantioselective heterogeneous catalyst, GO-[Mn(TPyP)tart], was prepared by covalent attachment of Mn(III) complex of H2TPyP via the propyl linkage to graphene oxide (GO) nanosheet and using chiral tartrate counter ion. The catalyst was characterized by Fourier transform infrared (FT-IR), diffuse reflectance ultraviolet–visible (DR UV–Vis) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and thermogravimetric analysis (TGA). The graphene-supported Mn-porphyrin showed higher activity for the enantioselective epoxidation of unfunctionalized olefins with molecular oxygen in the presence of isobutyraldehyde. It could be recovered easily and reused in asymmetric oxidation of styrene precursor in a five-step sequence without any considerable loss of its catalytic activity and selectivity. The obtained optically epoxide selectivities were achieved in 86% to 100%.
- Berijani, Kayhaneh,Farokhi, Afsaneh,Hosseini-Monfared, Hassan,Janiak, Christoph
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- A recyclable Mn-porphyrin catalyst for enantioselective epoxidation of unfunctionalized olefins using molecular dioxygen
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A magnetically separable chiral catalyst, Fe3O4/tart/Mn(TCPP)Cl, was prepared by the synthesis and immobilization of manganese-tetra(4-carboxyphenyl)porphyrin, Mn(TCPP)Cl, onto the chiral surface of magnetite nanoparticles (Fe3O4/tart-NPs; tart = l-tartaric acid) through the carboxylate groups. The solid catalyst was characterized by a variety of methods including XRD, FE-SEM, FT-IR and UV-Vis spectroscopy. The catalytic activity was tested in the epoxidation reactions of prochiral olefins with molecular oxygen. The reactions were carried out in acetonitrile as solvent with molecular oxygen in the presence of isobutyraldehyde as the stoichiometric oxidant. The catalyst showed consistently high conversion, selectivity and enantioselectivity to epoxide formation in the oxidation of a variety of terminal, cyclic and aromatic olefins. The catalyst showed little deactivation with time and it is easily recovered by magnetic filtration and could be reused four times with little or no loss in activity and selectivity.
- Farokhi, Afsaneh,Hosseini-Monfared, Hassan
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- Stereoselective benzylic hydroxylation of alkylbenzenes and epoxidation of styrene derivatives catalyzed by the peroxygenase of Agrocybe aegerita
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Here we report on the stereoselective benzylic hydroxylation and C1-C2 epoxidation of alkylbenzenes and styrene derivatives, respectively, by a heme-thiolate peroxygenase (EC 1.11.2.1) from the fungus Agrocybe aegerita. Benzylic hydroxylation led exclusively to the (R)-1-phenylalkanols. For (R)-1-phenylethanol, (R)-1-phenylpropanol and (R)-1-tetralol, the ee reached >99%. For longer chain lengths, the enantiomeric excesses (ee) and total turnover numbers (TTN) decreased while the number of by-products, e.g. 1-phenylketones, increased. Epoxidation of straight chain and cyclic styrene derivatives gave a heterogeneous picture and resulted in moderate to excellent ee values and TTN: e.g., in the case of (1R,2S)-cis-β-methylstyrene oxide formation, an ee >99% and a TTN of 110000 was achieved. Hydroxylation and epoxidation were true peroxygenations, which was demonstrated by the incorporation of 18O from H218O2 into the products. The use of fed-batch devices and varying feeding strategies for the substrate and co-substrate turned out to be a suitable approach to optimize peroxygenase catalysis.
- Kluge, Martin,Ullrich, Rene,Scheibner, Katrin,Hofrichter, Martin
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- Chiral salen Mn (III) immobilized on ZnPS-PVPA through alkoxyl-triazole for superior performance catalyst in asymmetric epoxidation of unfunctionalized olefins
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Chiral salen Mn (III) catalysts anchored onto ZnPS-PVPA via click chemistry are prepared and applied in asymmetric epoxidations of unfunctionalized olefins. Superior catalytic performances (conv%, up to >99; ee%, up to >99) are achieved in the epoxidations of α-methylstyrene, styrene, indene and 1-octene. According to 6-cyano-2,2-dimethylchromene and 6-nitro-2,2-dimethylchromene, configuration of epoxides are reversed. And then the catalysts are selective in not only oxidative systems, but also substrates. Moreover, superior reusability (yield, 82%; ee, 86%) after recycling for nine times could also be obtained, which provide the potential application in industry.
- Huang, Jing,Liu, Sirui,Ma, Yan,Cai, Jiali
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- A series of crystalline organic polymer-inorganic hybrid material zinc-phosphonate-phosphates synthesized in the presence of templates for superior performance catalyst support
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New types of organic copolymer-inorganic hybrid material zinc-phosphonate-phosphates are prepared with amines as templates. Notably, crystalline samples are obtained not with traditional methods but with simple reactions. Moreover, the samples are provide
- Huang, Jing,Cai, Jiali,Li, Chang Ming,Fu, Xiang Kai
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- Layered crystalline chiral salen Mn(III) complexes immobilized on organic polymer-inorganic hybrid zinc phosphonate-phosphate as efficient and reusable catalysts for the unfunctionalized olefin epoxidation
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Chiral Mn(III) salen complexes grafted on ZnPS-PVPA (zinc poly(styrene-phenylvinyl-phosphonate)-phosphate) upon alkyldiamines through a facile method are evaluated by the asymmetric epoxidation of unfunctionalized olefins. Superior catalytic performances
- Huang, Jing,Yuan, Li,Cai, Jiali,Chen, Xiaohong,Qi, Dengwei
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- Oxiranyl anion-mediated synthesis of highly enantiomerically enriched styrene oxide derivatives
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(Matrix presented) The stereospecific α-lithiation of optically active styrene oxides and the trapping reaction of the corresponding highly reactive intermediates with electrophiles to produce optically active styrene oxide derivatives are described. This methodology has been applied to the synthesis of an optically active oral antifungal agent of industrial interest.
- Capriati, Vito,Florio, Saverio,Luisi, Renzo,Salomone, Antonio
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- Multicore Artificial Metalloenzymes Derived from Acylated Proteins as Catalysts for the Enantioselective Dihydroxylation and Epoxidation of Styrene Derivatives
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Artificial metalloenzymes (AME′s) are an interesting class of selective catalysts, where the chiral environment of proteins is used as chiral ligand for a catalytic metal. Commonly, the active site of an enzyme is modified with a catalytically active metal. Here we present an approach, where the commercial proteins lysozyme (LYS) and bovine serum albumin (BSA) can be converted into highly active and enantioselective AME′s. This is achieved by acylation of the proteins primary amino groups, which affords the metal salts in the core of the protein. A series of differently acylated LYS and BSA were reacted with K2OsO2(OH)4, RuCl3, and Ti(OMe)4, respectively, and the conjugates were tested for their catalytic activity in dihydroxylation and epoxidation of styrene and its derivatives. The best suited system for dihydroxylation is fully acetylated LYS conjugated with K2OsO2(OH)4, which converts styrene to 1,2-phenylethanediol with an enantioselectivity of 95 % ee (S). BSA fully acylated with hexanoic acid and conjugated with three moles RuCl3 per mole protein shows the highest ee values for the conversion of styrene to the respective epoxide with enenatioselectivities of over 80 % ee (R), a TON of more than 2500 and a yield of up to 78 % within 24 h at 40 °C. LYS has two favored selective binding sites for the metal catalyst and BSA has even three. The AME′s with titanate in the active center invert the enantioselectivity of styrene epoxidation.
- Leurs, Melanie,Dorn, Bjoern,Wilhelm, Sascha,Manisegaran, Magiliny,Tiller, Joerg. C.
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- An achiral manganese salen catalyst encapsulated in a peptidic phosphonate homochiral solid for the enantioselective formation of diols by consecutive epoxidation and hydration reactions
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An insoluble, porous, amorphous, homochiral material based on a polypeptide titanium-phosphonate scaffold with an encapsulated achiral Mn III-salen was prepared and characterized. Consecutive epoxidation and hydration of styrene and its derivatives by aqueous hypochlorite in THF showed the highly enantioselective (>99%) formation of styrene diol derivatives.
- Milo, Anat,Neumann, Ronny
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- Asymmetric epoxidation of unfunctionalized olefins catalyzed by Mn(salen) axially immobilized onto insoluble polymers
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Chiral Mn(salen) complexes axially immobilized onto insoluble polymers by phenoxy group or phenyl sulfonic group afford comparable or even higher enantioselectivities than homogeneous Mn(salen) catalysts for the asymmetric epoxidation of various unfunctio
- Zhang, Huidong,Zhang, Yanmei,Li, Can
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- Reusable chiral salen Mn(III) complexes with phase transfer capability efficiently catalyze the asymmetric epoxidation of unfunctionalized olefins with NaClO
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A series of chiral salen Mn(III) polymers with build-in phase transfer capability was prepared by bridging the chiral salen Mn(III) units with polyethylene glycol (PEG)-based di-imidazolium ionic liquid (IL) side by side. Technologies of characterization
- Chen, Yaju,Tan, Rong,Zhang, Yaoyao,Zhao, Guangwu,Zheng, Weiguo,Luo, Rongchang,Yin, Donghong
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- Specific photobiocatalytic oxyfunctionalization reactions
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Turn a light on: Enantiospecific hydroxylation of nonactivated C-H bonds as well as epoxidations of C=C bonds are reported using a novel peroxidase from Agrocybe aegerita (AaeAPO). AaeAPO represents a more active and more versatile alternative to the current gold standard, chloroperoxidase. H2O 2 was produced in situ by photocatalytic reduction of O2 using simple flavin adenine mononucleotide (FMN) catalysts. Copyright
- Churakova, Ekaterina,Kluge, Martin,Ullrich, Rene,Arends, Isabel,Hofrichter, Martin,Hollmann, Frank
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- Enantioselective epoxidation of unfunctionalised olefins catalyzed by Mn(salen) complexes immobilized in porous materials via phenyl sulfonic group
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Heterogeneous chiral Mn(salen) catalysts axially immobilized on mesoporous materials via phenyl sulfonic groups result in remarkably higher ee values (up to 95%) for asymmetric epoxidation of unfunctionalised olefins. The Royal Society of Chemistry 2005.
- Zhang, Huidong,Xiang, Song,Li, Can
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- Ionic liquid-functionalized graphene oxide as an efficient support for the chiral salen Mn(iii) complex in asymmetric epoxidation of unfunctionalized olefins
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Imidazolium-based ionic liquid (IL)-functionalized graphene oxide (GO) was prepared and used to support chiral salen Mn(iii) complexes. Technologies of characterization suggested that the intact chiral complex was covalently appended on flat planes and ed
- Zheng, Weiguo,Tan, Rong,Yin, Shenfu,Zhang, Yaoyao,Zhao, Guangwu,Chen, Yaju,Yin, Donghong
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- A new heterogeneous chiral (salen)manganese(III) system for enantioselective epoxidation of non-functionalized olefins
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This communication describes the design and application of a novel catalytic epoxidation system derived from the initial immobilization of a homogeneous sulfonato (salen)Mn(III) complex on two solid carriers (silica gel and siliceous earth) and subsequent dispersion of the supported manganese complexes into ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) for recycling. The performance of chiral (salen)Mn(III) system in enantioselective epoxidation of olefins was investigated systematically. Even higher enantioselectivity than that of the homogeneous counterpart was obtained with similar catalytic activity. In particular, the best catalytic result is that the combination of the silica gel-supported (salen)Mn(III) catalyst and BMImPF6 affords 97-100% ee for epoxidation of α-methylstyrene, and high ee values were retained even after three cycles.
- Wei, Saili,Tang, Yuhai,Xu, Xiaoqian,Xu, Guojin,Yu, Yong,Sun, Yang,Zheng, Yuansuo
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- Structure-control in assembly of nanosheets: Novel chiral catalysts for the asymmetric epoxidation of α-methylstyrene without axial base
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Heterogeneous chiral catalysts with different structure, surface character and location of active species were assembled by salen Mn(III) complex and α-Zr(HPO4)2 nanosheets. The bumpy edge-accumulated surfaces of nanosheets lead the
- Hu, Chenhui,Zhang, Lihong,Zhang, Junfeng,Cheng, Liyuan,Zhai, Zheng,Li, Meng,Chen, Jing,Hou, Wenhua
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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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- Constraining asymmetric organometallic catalysts within mesoporous supports ZnPS-BrPPAS boosts their enantioselectivity
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Novel layered heterogeneous chiral salen Mn(III) catalysts are synthesized with organic-inorganic hybrid material ZnPS-BrPPAS as the support and employed in the asymmetric epoxidations of unfunctionalized olefins. Characterizations indicate that the diffe
- Huang, Jing,Yuan, Li,Cai, Jiali
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- Enhanced Turnover for the P450 119 Peroxygenase-Catalyzed Asymmetric Epoxidation of Styrenes by Random Mutagenesis
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A randomized library is constructed based on pET30a-CYP119-T214V plasmid. This library of random mutants of CYP119-T214V was screened by means of the reduced CO difference spectra and epoxidation of styrene. By using directed evolution, a new CYP119 quadr
- Wang, Li,Wei, Siping,Pan, Xianchao,Liu, Pingxian,Du, Xi,Zhang, Chun,Pu, Lin,Wang, Qin
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- Highly efficient asymmetric epoxidation of olefins with a chiral manganese-porphyrin covalently bound to mesoporous SBA-15: Support effect
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A chiral MnIII-porphyrin complex covalently bonded with mesoporous SBA-15 (SBA15-[Mn(TCPP-R?)Cl]) was synthesized and fully characterized. The heterogeneous SBA15-[Mn(TCPP-R?)Cl] exhibited remarkable catalytic activity toward enantioselective olefin epoxidation using O2 as terminal oxidant in the presence of isobutyraldehyde. The catalyst showed higher enantioselectivity than its homogeneous counterpart in the oxidation of α-methylstyrene. SBA15-[Mn(TCPP-R?)Cl] catalyzed epoxidation of styrene was achieved within 8?h and optically active styrene oxide was obtained in 89% ee and 90% yield. Likewise, styrene derivatives (trans-β-methylstyrene, indene), conjugated cis- and trans-disubstituted olefins (e.g. cis- and tans-stilbene) and terminal olefins were converted effectively to their corresponding epoxides in 63–99%?ee under the Mn(III)-catalyzed conditions. The catalyst could be recycled five times without any significant loss in activity.
- Farokhi, Afsaneh,Hosseini Monfared, Hassan
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- Collaborative effect of Mn-porphyrin and mesoporous SBA-15 in the enantioselective epoxidation of olefins with oxygen
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The rational design of heterogeneous, low cost transition metal complexes that can catalyze olefin with high enantioselectivity and activity has been a challenging goal for the synthetic chemist. In this study a chiral ion pair strategy was used for the synthesis of a biomimetic efficient manganese-tetrapyridylporphyrin (H2TPyP) catalyst for the asymmetric epoxidation of olefins with O2. Complex Mn-TPyP was covalently linked to mesoporous SBA-15 in heme-type environments and its counter ion was replaced by L-tartrate anion (SBA15-[Mn(TPyP)TA]). Chiral and achiral homogeneous analogous of Mn-TPyP were also prepared. The Mn-porphyrin confined in nanoreactors of SBA-15 exhibited enhanced activity (TOF = 652 h?1) and enantiomeric excess (ee 93%) compared with the value obtained when the same chiral catalyst functioned in homogeneous solution (TOF 97 h?1 and ee 83%) in the oxidation of 1-decene with O2/isobutyraldehyde. The high specific surface area, uniformly sized pore channels and site isolated active centers of the catalyst may contribute to the high activity and enantioselectivity. SBA15-[Mn(TPyP)TA] was structurally stable and could be recycled for repeated use. Total turnover number in the oxidation of styrene after five cycles was 47,400 with 86% epoxide selectivity and ee 86%.
- Berijani, Kayhaneh,Hosseini-Monfared, Hassan
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- Asymmetric epoxidation of unfunctionalized olefins accelerated by thermoresponsive self-assemblies in aqueous systems
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A novel thermoresponsive surfactant-type chiral salen MnIII catalyst was developed by axially grafting "smart" poly(N-isopropylacrylamide) (PNIPAAm) onto the metal center of a neat chiral salen MnIII complex. Characterization data su
- Zhang, Yaoyao,Tan, Rong,Zhao, Guangwu,Luo, Xuanfeng,Yin, Donghong
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- A magnetically recyclable Fe3O4@SiO2/Mn(III) chiral salen complex as a highly selective and versatile heterogeneous nanocatalyst for the oxidation of olefins and sulfides
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In this study, a new magnetically recoverable heterogeneous Mn(iii) nanocatalyst (MHMC) was developed by covalent grafting of a homogeneous chiral Mn(iii) salen complex (HMC) onto the surface of a Fe3O4/SiO2 core-shell. The structural and chemical nature of MHMC was characterized by different techniques. The catalytic activity of the MHMC and comparison with its homogeneous analogue were studied for the enantioselective epoxidation of various alkenes to epoxide compounds using tert-butyl hydroperoxide (TBHP) as an oxidant. The MHMC showed higher enantioselectivity and comparable catalytic reactivity to its homogeneous analogue with benefits such as facile recovery and recycling of the heterogeneous catalyst. The results showed that a higher enantioselectivity and yield were observed in the presence of N-methylmorpholine N-oxide (NMNO). The catalytic activity of this complex was also tested in the oxidation of sulfides using aqueous 30% H2O2 in excellent yields. The catalyst was reused for several runs without significant loss in activity and selectivity.
- Allahresani, Ali,Nasseri, Mohammad Ali
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- Manganes-Porphyrin as Efficient Enantioselective Catalyst for Aerobic Epoxidation of Olefins
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A chiral manganese porphyrin, [Mn(TCPP-Ind)Cl], was synthesized using cis-1-amino-2-indanol substituent. It showed remarkable catalytic activity and enantioselectivity in the epoxidation of olefins with O2/RCHO. Terminal olefins and styrene derivatives were successfully oxidized (> 99% ee). TON of 73,000 was achieved in the epoxidation of α-methylstyrene after five times recycling. Graphical Abstract: [Figure not available: see fulltext.].
- Farokhi, Afsaneh,Berijani, Kayhaneh,Hosseini-Monfared, Hassan
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- Enantioselective epoxidation of unfunctionalized olefins by Jacobsen's catalyst immobilized on amino-modified ZnPS-PVPA
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Catalytic asymmetric epoxidation of alkenes is a powerful method for the synthesis of chiral organic compounds. A recyclable chiral Jacobsen's catalyst immobilized on ZnPS-PVPA on diamines gave high catalytic activity (conversion > 99%, ee > 99%) in the asymmetric epoxidations of unfunctionalized olefins. The synergistic effect of the support ZnPS-PVPA and the linkage as well as chiral salen Mn center contributed to the chirality of the product. The stability (recycled nine times) and the ease of use in large scale reactions (200 times scale) indicated a catalyst useful for industrial use.
- Huang, Jing,Iuo, Yan,Cai, Jiali
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- Chiral salen Mn(III) immobilized on sulfoalkyl modified ZSP-IPPA as an effective catalyst for asymmetric epoxidation of unfunctionalized olefins
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Sulfoalkyl modified zirconium poly (styrene-isopropenyl phosphonate)-phosphate (ZPS-IPPA), with special structures of new type of organic-inorganic hybrid material were designed and synthesized for immobilization of the chiral salen Mn(III) Jacobsen's hom
- Tu, Xiaobo,Fu, Xiangkai,Hu, Xiaoyan,Li, Yuedong
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- A novel layered organic polymer-inorganic hybrid zinc poly (styrene-phenylvinylphosphonate)-phosphate immobilized chiral salen Mn(III) catalyst large-scale asymmetric epoxidation of unfunctionalized olefins
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A novel layered organic polymer-inorganic hybrid zinc poly (styrene-phenylvinylphosphonate)-phosphate (ZnPS-PVPA) has been synthesized under mild conditions and diphenol-modified ZnPS-PVPA was used to successfully immobilize the chiral salen Mn(III) by axial coordination. The obtained heterogeneous chiral catalysts exhibited excellent activities and enantioselectivities using sodium periodate as an oxidant for asymmetric epoxidation of unfunctionalized olefins, especially for the epoxidation of α-methylstyrene (conversion: up to 97%; ee: exceed 99%). Moreover, these synthesized catalysts were relatively stable and could be expediently separated from the reaction system, and could be recycled at least ten times without obvious loss of activity and enantioselectivity. These novel catalysts could be efficiently used in large-scale reactions with the enantioselectivity being maintained at the same level, which offer a great possibility for application in industry.
- Hu, Xiaoyan,Fu, Xiangkai,Xu, Jiangwei,Wang, Changwei
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- Layered zinc and lanthanum hydroxide nitrates hosting chiral sulphonato-(salen)manganese(III) complex catalyzed asymmetric epoxidation reactions
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Layered zinc and lanthanum hydroxide nitrates were first applied as two ion-exchangeable supports for immobilizing a chiral sulphonato-(salen) manganese(III) complex, and the resulted catalysts were characterized by FT-IR, elemental analysis, ICP-AES, TGA, conductivity, XRD, nitrogen physisorption, along with aqueous particle size and zeta potential. Heterogeneous catalysts showed moderate to good conversions and excellent enantioselectivities in epoxidation of styrene and α-methylstyrene when iodosylbenzene was employed as terminal oxidant. Furthermore, the superiority came from heterogeneity, and only filtration could lead to an effective separation of catalyst from product solution.
- Li, Xiaoyong,Shen, Qinchao,Zhang, Guangbin,Zhang, Donghua,Zheng, Aqun,Guan, Fang,Sun, Yang
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- Heterogeneous Jacobsen's catalyst on alkoxyl-modified zirconium poly (styrene-phenylvinylphosphonate)-phosphate (ZPS-PVPA) for asymmetric epoxidation
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Chiral Jacobsen's catalysts grafted onto alkoxyl-modified ZPS-PVPA exhibit excellent activities (conv%, up to 96; sele%, up to 96; ee%, up to >99) in the asymmetric epoxidations of unfunctionalized olefins. The superior stabilities and the comfortable dis
- Huang, Jing,Ding, Weigang,Cai, Jiali
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- Peroxygenase-Catalysed Epoxidation of Styrene Derivatives in Neat Reaction Media
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Biocatalytic oxyfunctionalisation reactions are traditionally conducted in aqueous media limiting their production yield. Here we report the application of a peroxygenase in neat reaction conditions reaching product concentrations of up to 360 mM.
- Alcalde, Miguel,Arends, Isabel W. C. E.,Hollmann, Frank,Paul, Caroline E.,Rauch, Marine C. R.,Tieves, Florian
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- An improved catalytic system for recycling OsO4 and chiral ligands in the asymmetric dihydroxylation of olefins
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A recyclable catalytic system for the asymmetric dihydroxylation of olefins was developed by using a mono-quaternized bis-cinchona alkaloid ligand 3 and OsO4 combined with PEG or an ionic liquid. Both the catalytic components could be recovered and reused in five consecutive reactions without any additional OsO4 or ligand. The catalytic system is effective in the AD reactions of seven olefins.
- Jiang, Ru,Kuang, Yongqing,Sun, Xiaoli,Zhang, Shengyong
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- The catalytic activity of new chiral salen complexes immobilized on MCM-41 by multi-step grafting in the asymmetric epoxidation
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The chiral salen Mn(III) complexes were heterogenized on the siliceous MCM-41 by a new grafting method using (3-aminopropyl) trimethoxysilane and 2,6-diformyl-4-tert-butylphenol. The immobilized chiral salen Mn(III) complexes were stable during the reacti
- Kim, Geon-Joong,Shin, Ji-Hoon
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- Grafting of a chiral Mn(iii) complex on graphene oxide nanosheets and its catalytic activity for alkene epoxidation
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A chiral Mn(iii) complex supported by a covalent grafting method on modified graphene oxide was synthesized using 3-chloropropyltrimethoxysilane as a reactive surface modifier. The heterogeneous catalyst was characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, ultraviolet-visible spectra, nitrogen adsorption-desorption isotherms, transmission electron microscopy and atomic absorption spectroscopy. The catalytic potential of the heterogeneous catalyst and comparison with its homogeneous counterpart were studied for enantioselective epoxidation of various alkenes using m-chloroperbenzoic acid as an oxidant and it showed high selectivity and comparable catalytic reactivity with its homogeneous analogue. In addition, higher enantioselectivity and higher yield were observed in the presence of 4-methylmorpholine N-oxide and pyridine N-oxide, respectively. The catalyst was reused for several runs without significant loss of activity and selectivity.
- Nasseri, Mohammad Ali,Allahresani, Ali,Raissi, Heidar
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- Chirally-Modified Graphite Oxide as Chirality Inducing Support for Asymmetric Epoxidation of Olefins with Grafted Manganese Porphyrin
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Abstract: A chirality inducer was prepared by graphite oxide (GO) functionalization with enantiopure l-tartrate (GO*) and used as asymmetric support for a covalently-linked manganese porphyrine complex [Mn(TPyP)OAc]. The thereby obtained heterogeneous catalyst, GO*-[Mn(TPyP)OAc], showed excellent performance and ee-values of 92–99% for the asymmetric epoxidation of prochiral olefins with O2 as oxidant and isobutyraldehyde as co-reductant in acetonitrile; linear terminal olefins with 54–76% conversion and quantitative conversion of aromatic olefins. The GO*-[Mn(TPyP)OAc] catalyst is highly active, recyclable, and at the same time simple and inexpensive to prepare with a chiral inducer from the chiral pool. The structure of the catalyst was elucidated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET analysis,?FT-IR, Raman, and photoluminescence spectroscopic methods. Graphic Abstract: Graphite oxide functionalized with an enantiopure group was used as a chirality inducer and asymmetric support for a Mn-porphyrine complex. The thereby obtained heterogeneous catalyst is an excellent enantioselective catalyst for the epoxidation of prochiral olefins.[Figure not available: see fulltext.].
- Ahadi, Elahe,Hosseini-Monfared, Hassan,Schlüsener, Carsten,Janiak, Christoph,Farokhi, Afsaneh
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- Monodisperse crosslinked pHEMA particle-supported chiral Mn(III)salen catalyst for asymmetric epoxidation of olefin
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Monodisperse crosslinked poly(hydroxyethyl methacrylate) particles (pHEMA) were synthesized for immobilization of the chiral Mn(III)salen homogeneous catalyst by axial coordination. The pHEMA-Mn(III)salen catalyst was subsequently characterized by FT-IR, UV and scanning electron microscopy. The results showed that, the heterogeneous Mn(III)salen catalysts also exhibited high activity and enantioselectivity compared to the homogeneous catalyst for the disubstituted cyclic indene and 6-cyano-2,2-dimethylchromene. Moreover, the catalysts were easily separated from the reaction systems and could be renewed several times without significant loss of catalytic activity. Meanwhile, the enantiomeric excess (ee) value remained at 80% in the eighth cycle. The pHEMA support, immobilized by Mn(III)salen, probably acted as a mediator of the reaction between the substrate and the oxidant, and enhanced the stability of the Mn(III)salen compound. Copyright
- Wei, Saili,Tang, Yuhai,Zhao, Ruiqin,Xu, Guojin,Zheng, Yuansuo
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- Asymmetric epoxidation of unfunctionalized olefins catalyzed by chiral salen-Mn (III) immobilized on alkoxyl-modified ZnPS-PVPA
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Novel layered heterogeneous chiral salen Mn (III) catalysts anchored onto ZnPS-PVPA by means of click chemistry are synthesized and employed in asymmetric epoxidations of unfunctionalized olefins. The catalysts manifest superior catalytic performances (conv%, up to >99; ee%, up to >99) according to the epoxidations of α-methylstyrene, styrene, indene and 1-octene. But for 6-cyano- 2,2-dimethylchromene and 6-nitro-2,2-dimethylchromene, configuration of epoxides are reversed. Moreover, the catalysts could still indicate comparable properties (yield, 82%; ee, 86%) after recycling for nine times and excellent functions in large-scale reactions, which paves the way for the application in industry.
- Huang, Jing,Xie, Junjie,Cai, Jiali
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- Enantioselective, Lewis Base-Catalyzed Carbosulfenylation of Alkenylboronates by 1,2-Boronate Migration
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A catalytic, enantioselective method for the preparation of chiral, non-racemic, alkylboronic esters bearing two vicinal stereogenic centers is described. The reaction proceeds via a 1,2-migration of a zwitterionic thiiranium-boronate complex to give excl
- Tao, Zhonglin,Robb, Kevin A.,Panger, Jesse L.,Denmark, Scott E.
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- Bioconversion of substituted styrenes to the corresponding enantiomerically pure epoxides by a recombinant Escherichia coli strain
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Enantiomerically pure epoxides are produced by bioconversion of the corresponding styrenes using a recombinant Escherichia coli strain containing the styrene monooxygenase gene cloned from Pseudomonas fluorescens ST. Different procedures were used to opti
- Bernasconi, Silvana,Orsini, Fulvia,Sello, Guido,Colmegna, Andrea,Galli, Enrica,Bestetti, Giuseppina
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- Studies on the synthesis of a chiral salen Mn (III) complex immobilised onto zirconium aminophosphonates and catalytic asymmetric epoxidation of α-methylstyrene
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A chiral salen Mn (III) complex has been immobilised onto zirconium aminophosphonates by axial coordination with different linkage arm lengths (CH2)n (n = 2-6), to give a series of heterogeneous catalysts. The catalysts exhibited good to excellent catalytic efficiency in the asymmetric epoxidation of α-methylstyrene. One heterogeneous catalyst, with n = 6, gave higher catalytic properties than the original chiral salen Mn (III) complex in the NaClO/PPNO system. It can be easily recovered and reused several times without significant loss of activity.
- Zhou, Liang
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- Highly stereoselective epoxidation with H2O2 catalyzed by electron-rich aminopyridine manganese catalysts
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Fast, efficient, and highly stereoselective epoxidation with H 2O2 is reached by manganese coordination complexes with e-rich aminopyridine tetradentate ligands. It is shown that the electronic properties of these catalysts vary systematically with the stereoselectivity of the O-atom transfer event and exert fine control over the activation of hydrogen peroxide, reducing the amount of carboxylic acid co-catalyst necessary for efficient operation.
- Cusso, Olaf,Garcia-Bosch, Isaac,Font, David,Ribas, Xavi,Lloret-Fillol, Julio,Costas, Miquel
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- A Robust Metal-Metalloporphyrin Framework Based upon a Secondary Building Unit of Infinite Nickel Oxide Chain
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Herein we report the construction of a robust metal-metalloporphyrin framework that is based upon a rare secondary building unit of infinite nickel oxide chain. The constructed MMPF-20 exhibits permanent porosity and selective adsorption of CO2 over CH4 as well as demonstrates interesting catalytic performances in the context of olefin epoxidation.
- Zhang, Weijie,Gao, Wenyang,Pham, Tony,Jiang, Pingping,Ma, Shengqian
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- Efficient rearrangement of epoxides catalyzed by a mixed-valent iron trifluoroacetate [Fe3O(O2CCF3)6(H2O)3]
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The mixed-valent oxo-centered triiron(III, III, II) trifluoroacetate complex [Fe2IIIFeIIO(O2CCF3)6(H2O)3] was prepared by reacting anhydrous iron(III) chloride with boiling trifluoroacetic acid under nitrogen. The non-hygroscopic and readily available mixed-valent triiron trifluoroacetate complex was found to be an efficient catalyst for the regioselective rearrangement of epoxides. A number of carbonyl compounds formed via the rearrangement of epoxides could be obtained by a simple filtration of the reaction mixture through a short plug of silica gel.
- Ertürk, Erkan,G?llü, Mehmet,Demir, Ayhan S.
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- Enantioselective aerobic oxidation of olefins by magnetite nanoparticles at room temperature: A chiral carboxylic acid strategy
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Asymmetric oxidations of organic compounds are limited in their synthetic scope and by practical factors, such as the use of complex catalyst synthesis. A simple and cheap nanostructured catalyst system comprising magnetite nanoparticles stabilized by l-(+)-tartaric acid (Fe3O4/tart-NPs) was successfully synthesized in diethylene glycol. The catalyst was characterized by FT-IR, TGA, ICP-AES, XRPD, SEM and dynamic light scattering (DLS). The catalytic activity of Fe3O4/tart-NPs dispersion in acetonitrile in the presence of isobutyraldehyde was studied in selective aerobic oxidation of olefins to form asymmetric epoxide, an important intermediate for the synthesis of biologically active compounds. In addition, the magnetically recoverable nanocatalyst Fe3O4/tart-NPs can be conveniently separated and recovered from the reaction system by applying an external magnetic field and reused for five cycles without the loss of activity after each cycle. These results demonstrate that the heterogeneous nanocatalysts possess potential applications for green and sustainable development. As synthesized nanoparticles of Fe3O4/tart-NPs are cheap and easy to synthesize asymmetric catalysts which were prepared without the involvement of difficult and cumbersome procedures for the synthesis of complicated asymmetric ligands. Possible reaction mechanisms were outlined.
- Hadian-Dehkordi, Leila,Hosseini-Monfared, Hassan
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- Immobilization of (tartrate-salen)Mn(III) polymer complexes into SBA-15 for catalytic asymmetric epoxidation of alkenes
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A series of (tartrate-salen)Mn(III) polymer complexes were prepared and immobilized into SBA-15, being subsequently employed as catalysts in the asymmetric epoxidation of alkenes. 1H NMR, FT-IR, UV–vis, elemental analysis, GPC and ICP-AES demonstrated the successful synthesis of polymer complexes, while powdered XRD, nitrogen physisorption and XPS studies proved the immobilization of polymer complexes into SBA-15. Both homogeneous and heterogeneous catalysis revealed that configurations of major epoxide products were still determined by salen chirality but e.e. values could be improved when tartrate and salen were configurationally identical. Combinations of (R,R)-salen with (R,R)-tartrate usually offered higher enantioselectivities. SBA-15 was satisfactory supporting material due to the high enantioselectivities and recycling yields obtained. The synthesized SBA-15-supported (tartrate-salen)Mn(III) catalysts showed continuous high enantioselectivities for epoxidation of α-methylstyrene, indicating great prospects for large-scale production.
- Jia, Yihong,ALOthman, Zeid A.,Liang, Rui,Cha, Shuangshuang,Li, Xiaoyong,Ouyang, Weiyi,Zheng, Aqun,Osman, Sameh M.,Luque, Rafael,Sun, Yang
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- Chiral porous poly(ionic liquid)s: Facile one-pot, one-step synthesis and efficient heterogeneous catalysts for asymmetric epoxidation of olefins
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Ionic liquids are potential media/solvents for asymmetric synthesis when combined with chiral catalysts, while most reported catalysts are homogenous, making them difficult to separate from the reaction systems. Herein, chiral porous poly(ionic liquid)s (
- Tian, Yabing,Wang, Jixia,Zhang, Shiguo,Zhang, Yan
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- Asymmetric azidohydroxylation of styrene derivatives mediated by a biomimetic styrene monooxygenase enzymatic cascade
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Enantioenriched azido alcohols are precursors for valuable chiral aziridines and 1,2-amino alcohols, however their chiral substituted analogues are difficult to access. We established a cascade for the asymmetric azidohydroxylation of styrene derivatives leading to chiral substituted 1,2-azido alcohols via enzymatic asymmetric epoxidation, followed by regioselective azidolysis, affording the azido alcohols with up to two contiguous stereogenic centers. A newly isolated two-component flavoprotein styrene monooxygenase StyA proved to be highly selective for epoxidation with a nicotinamide coenzyme biomimetic as a practical reductant. Coupled with azide as a nucleophile for regioselective ring opening, this chemo-enzymatic cascade produced highly enantioenriched aromatic α-azido alcohols with up to >99% conversion. A bi-enzymatic counterpart with halohydrin dehalogenase-catalyzed azidolysis afforded the alternative β-azido alcohol isomers with up to 94% diastereomeric excess. We anticipate our biocatalytic cascade to be a starting point for more practical production of these chiral compounds with two-component flavoprotein monooxygenases.
- Franssen, Maurice C. R.,Hollmann, Frank,Martínez-Montero, Lía,Paul, Caroline E.,Süss, Philipp,Schallmey, Anett,Tischler, Dirk
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p. 5077 - 5085
(2021/08/16)
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- Asymmetric epoxidation of unfunctionalized olefins with C2-symmetrical diphenol-derived axially coordinated homogeneous chiral bi-Mn(III) salen complexes
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A novel type of C2-symmetrical diphenol-derived and axially coordinated homogeneous chiral bi-Mn(III) salen complexes are synthesized and their catalytic effects in asymmetric epoxidation of unfunctionalized olefins are investigated in details. The results show that excellent enantioselectivities and high activities are achieved (enantioselectivities up to >99% in 99.9%) in the absence of expensive NMO. Compared with Jacobsen's catalyst, the configuration of C2-symmetrical homogeneous chiral bi-Mn(III) salen complex contribute to the catalytic reactivity and stability. Furthermore, these new homogeneous catalysts could be easily recovered and reused for 5 cycles without significant loss of their properties.
- Dong, Tianyi,Wu, Xiaoju,Cai, Jiali,Huang, Jing
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- Unprecedented Asymmetric Epoxidation of Isolated Carbon–Carbon Double Bonds by a Chiral Fluorous Fe(III) Salen Complex: Exploiting Fluorophilic Effect for Catalyst Design
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The first asymmetric epoxidation of isolated carbon–carbon double bonds by a chiral salen complex using ubiquitous Fe(III) as a center-metal is described. By simultaneously introducing fluorous tags and tert-butyl groups into the ligand of the salen compl
- Kobayashi, Yuki,Obayashi, Riho,Watanabe, Yuki,Miyazaki, Hiroki,Miyata, Issei,Suzuki, Yuta,Yoshida, Yukihiro,Shioiri, Takayuki,Matsugi, Masato
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supporting information
p. 2401 - 2408
(2019/03/26)
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- Dual activity of durable chiral hydroxyl-rich MOF for asymmetric catalytic reactions
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The quest to prepare of asymmetric heterogeneous catalysts with both effective Br?nsted acid sites (BASs) and Lewis acid sites is very significant challenge. Herein, we report the construction of a chiral metal-organic framework with two kinds of catalytic active sites (Lewis acid/Br?nsted acid). It contains coordinative unsaturation metal centers and chiral functional groups that have cooperation in the catalytic activity. In the synthesized CMOF, the chiral decoration of metal node was performed through the practical method: anions exchange hypothesis (post-synthetic exchange). For this aim, the elimination of framework fluorides happened by using the enantiopure auxiliary anions (L-(+)-tartrate anion (tart?)) that led to a chiral cationic MOF with eventual chemical formula [Cr3tart(H2O)2O(bdc)3]. XRD, BET, 1H NMR, SEM and EDX were employed to characterize of the present CMIL. Despite the chiral tartrate anions generate a chiral environment, they have main role in the activating of epoxide ring due to hydrogen-bonding interaction. Experiments show that the enantiopure tartrate-functionalized MIL-101(Cr) as a green asymmetric catalyst has the considerable performance in the enantioselective reactions due to chiral modified surface without remarkable loss in activity.
- Berijani, Kayhaneh,Morsali, Ali
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- Mild Iridium-Catalysed Isomerization of Epoxides. Computational Insights and Application to the Synthesis of β-Alkyl Amines
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The isomerization of epoxides to aldehydes using the readily available Crabtree's reagent is described. The aldehydes were transformed into synthetically useful amines by a one-pot reductive amination using pyrrolidine as imine-formation catalyst. The reactions worked with low catalyst loadings in very mild conditions. The procedure is operationally simple and tolerates a wide range of functional groups. A DFT study of its mechanism is presented showing that the isomerization takes place via an iridium hydride mechanism with a low energy barrier, in agreement with the mild reaction conditions. (Figure presented.).
- Cabré, Albert,Cabezas-Giménez, Juanjo,Sciortino, Giuseppe,Ujaque, Gregori,Verdaguer, Xavier,Lledós, Agustí,Riera, Antoni
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supporting information
p. 3624 - 3631
(2019/07/10)
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- A bottom up approach towards artificial oxygenases by combining iron coordination complexes and peptides
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Supramolecular systems resulting from the combination of peptides and a chiral iron coordination complex catalyze asymmetric epoxidation with aqueous hydrogen peroxide, providing good to excellent yields and high enantioselectivities in short reaction tim
- Cussó, Olaf,Giuliano, Michael W.,Ribas, Xavi,Miller, Scott J.,Costas, Miquel
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p. 3660 - 3667
(2017/07/11)
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- RETRACTED ARTICLE: Chiral Jacobsen's catalyst immobilized on zinc poly(styrene-phenylvinylphosphonate)-phosphate functionalized by diamine as highly efficient and reusable catalyst for alkene epoxidation
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Chiral Jacobsen's catalyst anchored on zinc poly(styrene-phenylvinylphosphonate)-phosphate (ZnPS-PVPA) functionalized by diamines shows superior catalytic activities (conversion up to 99%; enantiomeric excess up to 99%) in the enantioselective epoxidation
- Huang, Jing,Luo, Yan,Cai, Jiali
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p. 2397 - 2404
(2017/09/30)
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- A heterogenized chiral imino indanol complex of manganese as an efficient catalyst for aerobic epoxidation of olefins
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Herein, a new heterogenized chiral catalyst, GFC-[Mn(L)(OH)], was synthesized by grafting the complex [Mn(L)(OH)] on carbon-coated magnetic Fe3O4 nanoparticle-decorated reduced graphene oxide sheets (GFC) through an amine linkage (L = (1R,2S)-1-(N-salicylideneamino)-2-indanol). The catalyst was characterized via FT-IR, UV/vis, XRD, SEM, and vibrating sample magnetometer (VSM) techniques. It exhibited excellent activity and selectivity in the epoxidation of olefins with oxygen in the presence of isobutyraldehyde under mild conditions (conversion 38-98%; selectivity 65-98%; and enantioselectivity 58-100%, except for alpha-methylstyrene). Furthermore, the synergistic effect of the reduced graphene oxide support was observed on the increasing activity, epoxide selectivity, and enantioselectivity. The catalyst can be recovered via magnetic separation from the reaction mixture and recycled five times without any significant loss in its activity. The advantage of this development is the use of both the synergic effect of reduced graphene oxide and the magnetite nanoparticles to obtain an easily recyclable heterogeneous green catalyst. In addition, high asymmetric induction of a rigid indanol-based unit of the ligand results in high enantioselectivity.
- Abbasi, Vahideh,Hosseini-Monfared, Hassan,Hosseini, Seyed Majid
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p. 9866 - 9874
(2017/09/18)
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- A novel chiral manganese-tetraamide macrocycle complex covalently attached to magnetite as recyclable catalyst for aerobic asymmetric epoxidation of olefins
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A novel Mn complex containing N4-tetradentate tetraamide macrocyclic ligand (L) derived from chiral diethyl-2,3-benzylidene-L-tartrate and polyamidoamine dendrimer on Fe3O4@SiO2 surface was synthesized. The nanocomposite particles were investigated by SEM, XRD, VSM, EPR and FTIR. The nanocomposite showed high catalytic activity and selectivity for the epoxidation of linear terminal, cyclic and most of the aromatic olefins by O2 in the presence of isobutyraldehyde under mild conditions; epoxide selectivity 87–100%, enantiomeric excess 53–100%. The catalyst could be separated and recovered from the reaction system by applying an external magnetic field and reused for four cycles without the loss of activity after each cycle. Total TON of 16957 was obtained after four cycles.
- Hadian-Dehkordi, Leila,Hosseini-Monfared, Hassan,Aleshkevych, Pavlo
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p. 142 - 151
(2017/03/29)
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- Olefin epoxidation with chiral salen Mn(iii) immobilized on ZnPS-PVPA upon alkyldiamine
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The asymmetric epoxidation of unfunctionalized olefins using Jacobsen's catalyst is an effective strategy to achieve chiral epoxides. We report Jacobsen's catalysts anchored onto ZnPS-PVPA upon alkyldiamines as active heterogeneous catalysts for the epoxi
- Huang,Qi,Cai,Chen
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p. 19507 - 19514
(2016/03/01)
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- Engineering P450 Peroxygenase to Catalyze Highly Enantioselective Epoxidation of cis-β-Methylstyrenes
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P450 119 peroxygenase and its site-directed mutants are discovered to catalyze the enantioselective epoxidation of methyl-substituted styrenes. Two new site-directed P450 119 mutants, namely T213Y and T213M, which were designed to improve the enantioselectivity and activity for the epoxidation of styrene and its methyl substituted derivatives, were studied. The T213M mutant is found to be the first engineered P450 peroxygenase that shows highly enantioselective epoxidation of cis-β-methylstyrenes, with up to 91 % ee. Molecular modeling studies provide insights into the different catalytic activity of the T213M mutant and the T213Y mutant in the epoxidation of cis-β-methylstyrene. The results of the calculations also contribute to a better understanding of the substrate specificity and configuration control for the regio- and stereoselective peroxygenation catalyzed by the T213M mutant.
- Zhang, Chun,Liu, Ping-Xian,Huang, Lu-Yi,Wei, Si-Ping,Wang, Li,Yang, Sheng-Yong,Yu, Xiao-Qi,Pu, Lin,Wang, Qin
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p. 10969 - 10975
(2016/07/27)
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- Asymmetric epoxidation of unfunctionalized olefins catalyzed by Jacobsen's catalyst on alkoxyl-modified zirconium poly (styrene-phenylvinylphosphonate)-phosphate (ZPS-PVPA)
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New chiral Jacobsen's catalysts grafted onto alkoxyl-modified ZPS-PVPA are synthesized and applied in asymmetric epoxidations of unfunctionalized olefins. Specially, the supported catalysts indicate excellent catalytic activities (conv%, up to 96; sele%, up to 96; ee%, up to >99) in the absence of N-methylmorpholine N-oxide (NMO) by virtue of the special configurations of the catalysts. The superior stability (recycling for ten times) and the comfortable dispositions in large-scale reactions (such as 200 times) grant the potential application in industry to the heterogeneous catalysts.
- Huang, Jing,Luo, Yan,Cai, Jiali,Chen, Xiaohong
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- Reusable chiral salen Mn(III) complexes with phase transfer capability efficiently catalyze the asymmetric epoxidation of unfunctionalized olefins with NaClO
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A series of chiral salen Mn(III) polymers with build-in phase transfer capability was prepared by bridging the chiral salen Mn(III) units with polyethylene glycol (PEG)-based di-imidazolium ionic liquid (IL) side by side. Technologies of characterization
- Chen, Yaju,Tan, Rong,Zhang, Yaoyao,Zhao, Guangwu,Zheng, Weiguo,Luo, Rongchang,Yin, Donghong
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p. 106 - 115
(2015/05/05)
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- A series of crystalline organic polymer-inorganic hybrid material zinc-phosphonate-phosphates synthesized in the presence of templates for superior performance catalyst support
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New types of organic copolymer-inorganic hybrid material zinc-phosphonate-phosphates are prepared with amines as templates. Notably, crystalline samples are obtained not with traditional methods but with simple reactions. Moreover, the samples are provide
- Huang, Jing,Cai, Jiali,Li, Chang Ming,Fu, Xiang Kai
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- Synthesis of salen Mn(III) immobilized onto the ZnPS-PVPA modified by 1,2,3-triazole and their application for asymmetric epoxidation of olefins
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A series of chiral salen Mn(III) complexes immobilized onto ZnPS-PVPA modified by 1,2,3-triazole through click chemistry were synthesized. High yields and comparable enantioselectivities were achieved in asymmetric epoxidation of unfunctional olefins with
- Huang, Jing,Cai, Jiali,Feng, Hao,Liu, Zhiguo,Fu, Xiangkai,Miao, Qiang
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p. 5460 - 5467
(2013/07/05)
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- Synthesis of new binol based [1+1] macrocyclic chiral manganese(III) Schiff bases as catalysts for asymmetric epoxidation
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A series of new chiral binol based [1+1] macrocyclic Schiff bases have been synthesized in high yields in short reaction times via cyclo-condensation of dialdehydes with long tethers and chiral diamines. Macrocyclic Mn(salen) complexes containing N2
- Suresh, Paulsamy,Srimurugan, Sankareswaran,Dere, Ravindra T.,Ragavan, R. Venkat,Gopinath, Vadiraj Suphala
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p. 669 - 676
(2013/07/11)
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- Enantioselective epoxidation of nonfunctionalized alkenes catalyzed by recyclable new homochiral bis-diamine-bridged bi-Mn(salen) complexes
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Three new homochiral bis-diamine-bridged bi-Mn(salen) complexes were synthesized. Their catalysis on asymmetric epoxidation of α-methylstyrene, styrene and indene was studied with NaClO and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen's catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.
- Huang, Xuemei,Fu, Xiangkai,Jia, Ziyong,Miao, Qiang,Wang, Guoming
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p. 604 - 611
(2013/07/19)
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- A homogeneous chiral manganese(III)-salphe catalyst for enantioselective epoxidation of olefins
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A new chiral Mn(III)-Salphe catalyst was synthesized from natural amino acid (R)-phenylalanine and 3,5-di-tert-butyl-hydroxybenzaldehyde and applied to the asymmetric epoxidations of unfunctionalized olefins in ionic liquids. Satisfactory enantioselectivities (79% 4O Ac was unnecessary. We proposed that alcoholic hydroxyls in the Mn(III)-Salphe compound played the role of axial ligand. However, the reaction time was longer than when using Jacobsen's catalyst because of the structure of the Mn(III)-Salphe compound, in which coordination geometries by the two alcoholic hydroxyls with certain angles affected the substrate approaching the Mn(V) = 0 center. The chiral ligand was characterized by the combination of infrared, ultraviolet, and visible spectra and 1H NMR. Copyright
- Wei, Saili,Tang, Yuhai,Zhao, Ruiqin,Xu, Xiaoqian,Xu, Guojin,Yu, Yong,Zheng, Yuansuo
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supporting information
p. 2134 - 2146
(2013/07/25)
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- Salen Mn(iii) immobilized onto ZnPS-PVPA modified by 1,2,3-triazole as efficient and reusable catalysts for asymmetric epoxidation of olefins
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A series of novel types of chiral salen Mn(iii) anchored onto ZnPS-PVPA containing 1,2,3-triazole were synthesized by means of click chemistry. These supported catalysts were highly active and enantioselective (conversion up to 99%; ee up to 99%) in the a
- Cai, Jiali,Huang, Jing,Li, Chang Ming,Feng, Hao,Liu, Zhiguo
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p. 18661 - 18670
(2013/10/21)
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