1689-71-0Relevant articles and documents
Porphyrins and Azaporphines as Catalysts in Alkene Epoxidations with Peracetic Acid.
Banfi, Stafano,Montanari, Fernando,Quici, Silvio,Barkanova, Svetlana. V.,Kaliya, Oleg L.,et al.
, p. 2317 - 2320 (1995)
The reactivities of five MnIII(Cl) - phorphinoids were compared in the catalytic alkene epoxidations in CH3CN solution with peracetic acid as primary oxidant.Porphyrins 1 and 2 bearing Cl and NO2 substituents showed the best efficiency while te
Mn(III)-Iodosylarene Porphyrins as an Active Oxidant in Oxidation Reactions: Synthesis, Characterization, and Reactivity Studies
Guo, Mian,Lee, Yong-Min,Seo, Mi Sook,Kwon, Yong-Ju,Li, Xiao-Xi,Ohta, Takehiro,Kim, Won-Suk,Sarangi, Ritimukta,Fukuzumi, Shunichi,Nam, Wonwoo
, p. 10232 - 10240 (2018)
Mn(III)-iodosylarene porphyrin adducts, [Mn(III)(ArIO)(Porp)]+, were synthesized by reacting electron-deficient Mn(III) porphyrin complexes with iodosylarene (ArIO) at -60 °C and characterized using various spectroscopic methods. The [Mn(III)(ArIO)(Porp)]+ species were then investigated in the epoxidation of olefins under stoichiometric conditions. In the epoxidation of olefins by the Mn(III)-iodosylarene porphyrin species, epoxide was formed as the sole product with high chemoselectivities and stereoselectivities. For example, cyclohexene oxide was formed exclusively with trace amounts of allylic oxidation products; cis- and trans-stilbenes were oxidized to the corresponding cis- and trans-stilbene oxides, respectively. In the catalytic epoxidation of cyclohexene by an electron-deficient Mn(III) porphyrin complex and sPhIO at low temperature (e.g., -60 °C), the Mn(III)-iodosylarene porphyrin species was evidenced as the active oxidant that effects the olefin epoxidation to give epoxide as the product. However, at high temperature (e.g., 0 °C) or in the case of using an electron-rich manganese(III) porphyrin catalyst, allylic oxidation products, along with cyclohexene oxide, were yielded, indicating that the active oxidant(s) was not the Mn(III)-iodosylarene adduct but probably high-valent Mn-oxo species in the catalytic reactions. We also report the conversion of the Mn(III)-iodosylarene porphyrins to high-valent Mn-oxo porphyrins under various conditions, such as at high temperature, with electron-rich porphyrin ligand, and in the presence of base (OH-). The present study reports the first example of spectroscopically well-characterized Mn(III)-iodosylarene porphyrin species being an active oxidant in the stoichiometric and catalytic oxidation reactions. Other aspects, such as one oxidant versus multiple oxidants debate, also were discussed.
Studies on photochemical reactions of air pollutants. VIII. Photochemical epoxidation of olefins with NO2 in a solid-gas phase system
Nojima,Ohya,Kanno,Hirobe
, p. 4500 - 4506 (1982)
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The role of solvent friction in an orbital symmetry controlled reaction: Ring closure of a carbonyl ylide to cis-2,3-diphenyloxirane
Lipson, Matthew,Peters, Kevin S.
, p. 1691 - 1696 (1998)
The dynamics of the orbital symmetry controlled ring closure of the trans-ylide, formed upon the 266 nm photolysis of trans-2,3-diphenyloxirane, to produce cis-2,3-diphenyloxirane is examined in a variety of n-alkane solvents as a function of temperature. An unsuccessful attempt was made to model the kinetics within the theoretical framework developed by Kramers for a one-dimensional reaction coordinate. A model developed by Grote and Hynes that employs a frequency-dependent friction was found to give a significantly better fit to the experimental data. The possibility that a multidimensional reaction coordinate is necessary to describe the reaction dynamics is discussed.
A novel and efficient catalytic epoxidation of olefins with adducts derived from methyltrioxorhenium and chiral aliphatic amines
Vezzosi, Stefano,Guimerais Ferre, Anna,Crucianelli, Marcello,Crestini, Claudia,Saladino, Raffaele
, p. 262 - 269 (2008)
Nitrogen-based adducts derived from methyltrioxorhenium(VII) and chiral aliphatic amines have been synthesized and applied to the efficient catalytic epoxidation of olefins with urea hydrogen peroxide complex as the primary oxidant. These complexes retain their catalytic activity when microencapsulated in polystyrene. A moderate steroinduction was obtained in the epoxidation of prochiral olefins with complexes between methyltrioxorhenium and chiral trans-1,2-cyclohexyldiamine. The values of steroinduction were found to increase after the microencapsulation process.
Asymmetric Epoxidation of Unfunctionalized Olefins Using Novel Chiral Dihydroisoquinolinium Salts as Organocatalysts
Ali, K. Ben
, p. 638 - 646 (2021/06/02)
Abstract: Two new non-racemic chiral dihydroisoquinolinium salts with N-substituents bulkier than a methyl group have been synthesized from (1S,2R)-norephedrine. These salts were used to catalyze asymmetric epoxidation of a series of prochiral olefins. One of the two new catalysts provided higher enantioselectivities (up to 66% ee) than the reference salt containing an N-methyl substituent.
Nonheme manganese(III) complexes for various olefin epoxidation: Synthesis, characterization and catalytic activity
Lee, Sojeong,Park, Soyoung,Lee, Myoung Mi,Lee, Jiyoung,Kim, Cheal
, (2021/03/14)
Three mononuclear imine-based non-heme manganese(III) complexes with tetradentate ligands which have two deprotonated phenolate moieties, ([(X2saloph)Mn(OAc)(H2O)], 1a for X = Cl, 1b for X = H, and 1c for X = CH3, saloph = N,N-o-phenylenebis(salicylidenaminato)), were synthesized and characterized by 1H NMR, 13C NMR, ESI-Mass and elemental analysis. MnIII complexes catalysed efficiently various olefin epoxidation reactions with meta-chloroperbenzoic acid (MCPBA) under the mild condition. MnIII complexes 1a and 1c with the electron-withdrawing group -Cl and electron-donating group –CH3 showed little substituent effect on the epoxidation reactions. Product analysis, Hammett study and competition experiments with cis- and trans-2-octene suggested that MnIV = O, MnV = O, and MnIII-OOC(O)R species might be key oxidants in the epoxidation reaction under this catalytic system. In addition, the use of PPAA as a mechanistic probe demonstrated that Mn-acylperoxo intermediate (MnIII-OOC(O)R) 2 generated from the reaction of peracid with manganese complexes underwent both the heterolysis and the homolysis to produce MnV = O (3) or MnIV = O species (4). Moreover, the MnIII-OOC(O)R 2 species could react directly with the easy-to-oxidize substrate to give epoxide, whereas the species 2 might not be competent to the difficult-to-oxidize substrate for the epoxidation reaction.
Proton Switch in the Secondary Coordination Sphere to Control Catalytic Events at the Metal Center: Biomimetic Oxo Transfer Chemistry of Nickel Amidate Complex
Kim, Soohyung,Jeong, Ha Young,Kim, Seonghan,Kim, Hongsik,Lee, Sojeong,Cho, Jaeheung,Kim, Cheal,Lee, Dongwhan
supporting information, p. 4700 - 4708 (2021/02/12)
High-valent metal-oxo species are key intermediates for the oxygen atom transfer step in the catalytic cycles of many metalloenzymes. While the redox-active metal centers of such enzymes are typically supported by anionic amino acid side chains or porphyrin rings, peptide backbones might function as strong electron-donating ligands to stabilize high oxidation states. To test the feasibility of this idea in synthetic settings, we have prepared a nickel(II) complex of new amido multidentate ligand. The mononuclear nickel complex of this N5 ligand catalyzes epoxidation reactions of a wide range of olefins by using mCPBA as a terminal oxidant. Notably, a remarkably high catalytic efficiency and selectivity were observed for terminal olefin substrates. We found that protonation of the secondary coordination sphere serves as the entry point to the catalytic cycle, in which high-valent nickel species is subsequently formed to carry out oxo-transfer reactions. A conceptually parallel process might allow metalloenzymes to control the catalytic cycle in the primary coordination sphere by using proton switch in the secondary coordination sphere.
