86952-89-8Relevant academic research and scientific papers
A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles
Rossi-Fernández, Lucía,Dorn, Viviana,Radivoy, Gabriel
supporting information, p. 519 - 526 (2021/03/31)
A new heterogeneous catalytic system consisting of cobalt nanoparticles (CoNPs) supported on MgO and tert-butyl hydroperoxide (TBHP) as oxidant is presented. This CoNPs@MgO/t-BuOOH catalytic combination allowed the epoxidation of a variety of olefins with good to excellent yield and high selectivity. The catalyst preparation is simple and straightforward from commercially available starting materials and it could be recovered and reused maintaining its unaltered high activity.
SO2F2-Mediated Epoxidation of Olefins with Hydrogen Peroxide
Ai, Chengmei,Zhu, Fuyuan,Wang, Yanmei,Yan, Zhaohua,Lin, Sen
, p. 11928 - 11934 (2019/10/02)
An inexpensive, mild, and highly efficient epoxidation protocol has been developed involving bubbling SO2F2 gas into a solution of olefin, 30% aqueous hydrogen peroxide, and 4 N aqueous potassium carbonate in 1,4-dioxane at room temperature for 1 h with the formation of the corresponding epoxides in good to excellent yields. The novel SO2F2/H2O2/K2CO3 epoxidizing system is suitable to a variety of olefinic substrates including electron-rich and electron-deficient ones.
Remarkable increase in the rate of the catalytic epoxidation of electron deficient styrenes through the addition of Sc(OTf)3 to the MnTMTACN catalyst
Nodzewska, Aneta,Watkinson, Michael
supporting information, p. 1461 - 1464 (2018/02/19)
The effect of Lewis acids on the catalytic activity of [Mn2(μ-O)3(TMTACN)2](PF6)2 in the epoxidation of styrenes using hydrogen peroxide as the oxidant has shown that the addition of Sc(OTf)3 at low catalytic loading results in a very significant increase in the efficiency of the catalyst and a reduction of the reaction time to only 3 minutes in most cases.
Regioselective hydrosilylation of epoxides catalysed by nickel(II) hydrido complexes
Wenz, Jan,Wadepohl, Hubert,Gade, Lutz H.
supporting information, p. 4308 - 4311 (2017/04/21)
Bench-stable nickel fluoride complexes bearing NNN pincer ligands have been employed as precursors for the regioselective hydrosilylation of epoxides at room temperature. A nickel hydride assisted epoxide opening is followed by the cleavage of the newly formed nickel oxygen bond by σ-bond metathesis with a silane.
The Activation of Carboxylic Acids via Self-Assembly Asymmetric Organocatalysis: A Combined Experimental and Computational Investigation
Monaco, Mattia Riccardo,Fazzi, Daniele,Tsuji, Nobuya,Leutzsch, Markus,Liao, Saihu,Thiel, Walter,List, Benjamin
supporting information, p. 14740 - 14749 (2016/11/18)
The heterodimerizing self-assembly between a phosphoric acid catalyst and a carboxylic acid has recently been established as a new activation mode in Br?nsted acid catalysis. In this article, we present a comprehensive mechanistic investigation on this activation principle, which eventually led to its elucidation. Detailed studies are reported, including computational investigations on the supramolecular heterodimer, kinetic studies on the catalytic cycle, and a thorough analysis of transition states by DFT calculations for the rationalization of the catalyst structure-selectivity relationship. On the basis of these investigations, we developed a kinetic resolution of racemic epoxides, which proceeds with high selectivity (up to s = 93), giving the unreacted epoxides and the corresponding protected 1,2-diols in high enantiopurity. Moreover, this approach could be advanced to an unprecedented stereodivergent resolution of racemic α-chiral carboxylic acids, thus providing access to a variety of enantiopure nonsteroidal anti-inflammatory drugs and to α-amino acid derivatives.
One-Pot Synthesis of N-tert-Butylsulfinylimines and Homoallylamine Derivatives from Epoxides
Lahosa, Alejandro,Foubelo, Francisco,Yus, Miguel
supporting information, p. 4067 - 4076 (2016/08/24)
The reaction of epoxides with tert-butanesulfinamide in the presence of a Lewis acid, such as erbium triflate or boron trifluoride–diethyl ether, in THF as solvent, under microwave or thermal activation, produces N-tert-butylsulfinylimines in reasonable yields. Aromatic and gem-disubstituted and trisubstituted alkyl epoxides performed better than mono-alkyl-substituted compounds. After imine formation, a subsequent indium-promoted allylation can be carried out in the same reaction flask in a single synthetic operation leading to homoallylamine derivatives with generally high yields.
Catalytic Enantioselective Conversion of Epoxides to Thiiranes
Liao, Saihu,Leutzsch, Markus,Monaco, Mattia Riccardo,List, Benjamin
supporting information, p. 5230 - 5233 (2016/05/19)
A highly efficient and enantioselective Br?nsted acid catalyzed conversion of epoxides to thiiranes has been developed. The reaction proceeds in a kinetic resolution, furnishing both epoxide and thiirane in high yields and enantiomeric purity. Heterodimer formation between the catalyst and sulfur donor affords an effective way to prevent catalyst decomposition and enables catalyst loadings as low as 0.01 mol %.
Oxidation of styrene and of some derivatives with H2O 2 catalyzed by novel imidazolium-containing manganese porphyrins: A mechanistic and thermodynamic interpretation
De Paula, Rodrigo,Sim?es, Mário M.Q.,Neves, M. Graa P.M.S.,Cavaleiro, José A.S.
experimental part, p. 1 - 11 (2011/10/05)
The oxidation of styrene and derivatives with H2O2 catalyzed by manganese porphyrins in acetonitrile is described. The effect of the imidazolium substituent on the catalytic efficiency has been also considered. The thermodynamic analysis has indicated that enthalpy rules styrene oxidation when catalysts Mn(Porph)-1 and Mn(Porph)-2 are used whereas the entropy is the driven force for Mn(Porph)-3 and Mn(Porph)-4 catalyzed reactions. Interestingly, an enthalpy-entropy compensation phenomenon is observed when comparing the thermodynamic results obtained for catalysts Mn(Porph)-3 and Mn(Porph)-4. Hammett plots for the studied manganese porphyrins provided small ρ-values, and this is typical for multi-step reactions, indicating that there is no significant charge separation in the transition state. For Mn(Porph)-1 and Mn(Porph)-2 the formation of multiple active species can be put forward whereas for Mn(Porph)-3 and Mn(Porph)-4 a concerted-type mechanism, via metalloxetane intermediate, fits well with the values obtained for those catalysts. The imidazolium-based catalysts have shown to be efficient catalysts in styrene and derivatives oxidation with hydrogen peroxide.
A simple and versatile method for alkene epoxidation using aqueous hydrogen peroxide and manganese salophen catalysts
Liu, Shih-Yuan,Nocera, Daniel G.
, p. 1923 - 1926 (2007/10/03)
We describe a simple and versatile method for the catalytic epoxidation of a broad range of olefins (e.g., ketones, esters, and alkyl halides) with aqueous H2O2 using manganese salophen catalysts. Low catalyst loading, short reaction times, and a simple reaction setup (e.g., no pH buffer is required) are salient features of the system, which unites the benefits of H2O2 as an oxidant with the versatility and modularity of salen-based catalysts.
Trimanganese complexes bearing bidentate nitrogen ligands as a highly efficient catalyst precursor in the epoxidation of alkenes
Kang, Byungman,Kim, Min,Lee, Junseong,Do, Youngkyu,Chang, Sukbok
, p. 6721 - 6727 (2007/10/03)
A series of trinuclear manganese complexes coordinated with neutral bidentate nitrogen ligands, [Mn3L2-(OAc)6], were prepared from manganese acetate and the corresponding ligands. Using peracetic acid as the oxidant, the air- and moisture-stable manganese clusters exhibited excellent catalytic activity and selectivity in the epoxidation of olefins under mild conditions. The highest activity was observed with a trinuclear complex containing a 2-pyridylimino ligand, [Mn3(ppei) 2(OAc)6] (ppei = 2-pyridinal-1-phenylethylimine). With this system, the substrate scope was extremely wide to include terminal and electron-deficient double bonds of both aliphatic and aromatic alkenes. The high activity was undiminished under the reaction conditions even directly using a mixture of the pyridylimino ligands and manganese acetates, making this process more convenient. It was also observed that analogous trinuclear complexes, such as [Mn3(bipy)2(OAc)6] and [Mn 3(phen)2(OAc)6], displayed excellent activities. While radical intermediacy was inferred from the product distribution, kinetic data revealed that the epoxidation is roughly first-order in manganese cluster precursor and oxidant, respectively, and zero-order in olefin. These results led us to propose that the trinuclear complexes [Mn 3L2(OAc)6] serve as catalyst precursors that dissociate into monomeric species with the formulation of [MnL 2(OAc)2] under the reaction conditions.
