33669-38-4Relevant academic research and scientific papers
Olefin epoxidation by a (salen)Mn(III) catalyst covalently grafted on glass beads
Trusso Sfrazzetto, Giuseppe,Millesi, Salvatrice,Pappalardo, Andrea,Toscano, Rosa Maria,Ballistreri, Francesco P.,Tomaselli, Gaetano A.,Gulino, Antonino
, p. 673 - 679 (2015)
The asymmetric epoxidation of unfunctionalized prochiral olefins catalyzed by chiral (salen)Mn(III) complexes is an important viable route to obtain chiral epoxides. Recently we proposed a monolayer of (salen)Mn(III) molecules on functionalized flat silica substrates as an active heterogeneous catalyst for enantioselective epoxidation of 6-cyano-2,2-dimethylchromene with huge turnover values. In the present study we synthesized a monolayer of modified (salen)Mn(III) molecules on previously functionalized glass bead substrates in order to increase the active surface area. The catalyst activity of this system was tested with different olefins and in some cases we observed enantioselectivity higher than in solution. The system was reused up to seven times with no variation in performance.
A General Regioselective Synthesis of Alcohols by Cobalt-Catalyzed Hydrogenation of Epoxides
Beller, Matthias,Junge, Kathrin,Leischner, Thomas,Li, Wu,Liu, Weiping
supporting information, p. 11321 - 11324 (2020/05/16)
A straightforward methodology for the synthesis of anti-Markovnikov-type alcohols is presented. By using a specific cobalt triphos complex in the presence of Zn(OTf)2 as an additive, the hydrogenation of epoxides proceeds with high yields and selectivities. The described protocol shows a broad substrate scope, including multi-substituted internal and terminal epoxides, as well as a good functional-group tolerance. Various natural-product derivatives, including steroids, terpenoids, and sesquiterpenoids, gave access to the corresponding alcohols in moderate-to-excellent yields.
Covalently functionalized carbon nanoparticles with a chiral Mn-Salen: A new nanocatalyst for enantioselective epoxidation of alkenes
Zammataro, Agatino,Gangemi, Chiara Maria Antonietta,Pappalardo, Andrea,Toscano, Rosa Maria,Puglisi, Roberta,Nicotra, Giuseppe,Fragalà, Maria Elena,Tuccitto, Nunzio,Sfrazzetto, Giuseppe Trusso
supporting information, p. 5255 - 5258 (2019/05/08)
A new protocol to obtain carbon nanoparticles (CNPs) covalently functionalized with a chiral Mn-Salen catalyst is described here. The new nanocatalyst (CNPs-Mn-Salen) was tested in the enantioselective epoxidation of some representative alkenes (CN-chromene, 1,2-dihydronaphthalene and cis-β-ethyl styrene), obtaining better enantiomeric excess values than that of the catalyst single molecule, highlighting the role of the nanostructure in the enantioselectivity.
A bottom up approach towards artificial oxygenases by combining iron coordination complexes and peptides
Cussó, Olaf,Giuliano, Michael W.,Ribas, Xavi,Miller, Scott J.,Costas, Miquel
, p. 3660 - 3667 (2017/07/11)
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
Stable Copper Nanoparticle Photocatalysts for Selective Epoxidation of Alkenes with Visible Light
Huang, Yiming,Liu, Zhe,Gao, Guoping,Xiao, Gang,Du, Aijun,Bottle, Steven,Sarina, Sarina,Zhu, Huaiyong
, p. 4975 - 4985 (2017/08/17)
Selective epoxidation of various alkenes with molecular oxygen (O2) under mild conditions is a longstanding challenge in achieving syntheses of epoxides. Cu-based catalysts have been found to be catalytically active for selective epoxidations. However, the application of copper nanoparticles (CuNPs) for photocatalyzed epoxidations is encumbered by the instability of CuNPs in air. Herein we report that CuNPs supported on titanium nitride (TiN) without additional stabilizers not only are stable in air but also can catalyze selective epoxidation of various alkenes with O2 or even air as a benign oxidant under light irradiation. CuNPs remain in the metallic state due to the significant charge transfer that occurs between CuNPs and TiN. The epoxidation is driven by visible light irradiation at moderate temperatures, achieving good to high yields and excellent selectivity. The photocatalytic process is applicable to the selective epoxidation of various alkenes. In this photocatalytic system, reactant alkenes chemically adsorb on CuNPs, forming Cu-alkene surface complexes, and light irradiation can activate the complexes for reaction. The cyclic ether solvent also plays a key role, reacting with O2 on the surface of CuNPs under light irradiation, yielding oxygen adatoms. The activated surface complexes react with the adatoms, yielding the corresponding epoxides. Analysis of the influence of irradiation wavelength and intensity on the epoxidation suggests that light-excited electrons of CuNPs drive the reaction. The adatoms formed react with alkenes, producing the final product epoxides. We also observed interesting product stereoselectivity, predominantly generating the trans isomers for the epoxidation of stilbene (up to 97%). The findings reported here not only provide an effective and selective reaction system for alkene epoxidations but also are a step toward demonstrating the practical use of CuNPs as photocatalysts for various applications.
Efficient and convenient epoxidation of alkenes to epoxides with H2O2 catalyzed by Co(OAc)2 in ionic liquid [C12py][PF6]
Hu, Yu-Lin,Liu, Yi-Wen,Li, De-Jiang
, p. 2179 - 2184 (2015/10/19)
A simple, efficient, and eco-friendly procedure for the epoxidation of alkenes to epoxides with H2O2 catalyzed by Co(OAc)2 in ionic liquid [C12py][PF6] has been developed. The reactions were carried out with alkene, Co(OAc)2 (0.1 mmol), [C12py][PF6] (10 mL), and H2O2 (30 %, 11 mmol) at room temperature for 2-6 h. This atom-economical protocol affords the target products in good to high yields (88-98 %). The products can be separated by a simple extraction with organic solvent, and the catalytic system can be recycled and reused without loss of catalytic activity. Graphical abstract: A simple, efficient, and eco-friendly procedure for the epoxidation of alkenes to epoxides with H2O2 catalyzed by Co(OAc)2 in ionic liquid [C12py][PF6] has been developed.[Figure not available: see fulltext.]
Asymmetric epoxidation of styrene derivatives by styrene monooxygenase from Pseudomonas sp. LQ26: Effects of α- And β-substituents
Lin, Hui,Liu, Yan,Wu, Zhong-Liu
experimental part, p. 134 - 137 (2011/04/27)
Recombinant Escherichia coli expressing a styrene monooxygenase, StyAB2, from Pseudomonas sp. LQ26 was applied to synthesize a range of chiral epoxides from conjugated styrene derivatives with excellent (>99%) enantioselectivity in most cases. The substrate preference was studied with a special focus on the steric effect of α- and β-substituents.
Ruthenium clay catalyzed chemoselective hydrogenation of unsaturated esters, epoxides, sulfones and phosphonates
Aldea, Raluca,Alper, Howard
, p. 349 - 354 (2007/10/03)
Ru-clays were prepared using montmorillonite-PPh2 or montmorillonite-bpy and RuCl3·H2O. The clays obtained were found to be effective catalysts for the reduction of unsaturated esters, epoxides, sulfones and phosphonates.
Chemoselective Hydrogenation of the Double Bond of Vinyl Epoxides with Homogeneous Palladium and Iridium Catalysts
Cho, In Sik,Lee, Byeongno,Alper, Howard
, p. 6009 - 6012 (2007/10/02)
The selective hydrogenation of the double bond of vinyl epoxides is catalyzed by either the species generated by treatment of the binuclear palladium complex, t2PH)PdPBut2>2 with oxygen, or by the cationic iridium(I) complex, BF4, to produce the corresponding saturated epoxides at room temperature, and with good selectivity.
