10152-58-6Relevant articles and documents
Microbiological transformations 32: Use of epoxide hydrolase mediated biohydrolysis as a way to enantiopure epoxides and vicinal diols: Application to substituted styrene oxide derivatives
Pedragosa-Moreau,Archelas,Furstoss
, p. 4593 - 4606 (1996)
The biohydrolyses of various substituted styrene oxide derivatives using the fungi Aspergillus niger or Beauveria sulferescens are described. The results obtained show that this methodology allows the preparation of enantiomerically enriched epoxides and diols via enantioselective and regioselective hydration. The comparative study of the results obtained suggests that these hydrolyses operate following different mechanisms and a model of the corresponding active sites is proposed.
Ruthenium-catalyzed asymmetric epoxidation of olefins using H 2O2, part II: Catalytic activities and mechanism
Tse, Man Kin,Bhor, Santosh,Klawonn, Markus,Anilkumar, Gopinathan,Jiao, Haijun,Spannenberg, Anke,Doebler, Christian,Magerlein, Wolfgang,Hugl, Herbert,Beller, Matthias
, p. 1875 - 1888 (2006)
Asymmetric epoxidation of olefins with 30% H2O2 in the presence of [Ru(pybox)(pydic)] 1 and [Ru(pyboxazine)(pydic)] 2 has been studied in detail (pybox = pyridine-2,6-bisoxazoline, pyboxazine = pyridine-2,6-bisoxazine, pydic = 2,6-pyridinedi-carboxylate). 35 Ruthenium complexes with sterically and electronically different substituents have been tested in environmentally benign epoxidation reactions. Mono-, 1,1-di-, cis- and trans-1,2-di-, tri-, and tetra-substituted aromatic olefins with versatile functional groups can be epoxidized with this type of catalyst in good to excellent yields (up to 100%) with moderate to good enantioselectivies (up to 84% ee). Additive and solvent effects as well as the relative rate of reaction with different catalysts have been established. It is shown that the presence of weak organic acids or an electron-withdrawing group on the catalyst increases the reactivity. New insights on the reaction intermediates and reaction pathway of the ruthenium-catalyzed epoxidation are proposed on the basis of density functional theory calculation and experiments.
Effect of the Ligand Backbone on the Reactivity and Mechanistic Paradigm of Non-Heme Iron(IV)-Oxo during Olefin Epoxidation
Biswas, Jyoti Prasad,Ansari, Mursaleem,Paik, Aniruddha,Sasmal, Sheuli,Paul, Sabarni,Rana, Sujoy,Rajaraman, Gopalan,Maiti, Debabrata
, p. 14030 - 14039 (2021)
The oxygen atom transfer (OAT) reactivity of the non-heme [FeIV(2PyN2Q)(O)]2+ (2) containing the sterically bulky quinoline-pyridine pentadentate ligand (2PyN2Q) has been thoroughly studied with different olefins. The ferryl-oxo complex 2 shows excellent OAT reactivity during epoxidations. The steric encumbrance and electronic effect of the ligand influence the mechanistic shuttle between OAT pathway I and isomerization pathway II (during the reaction stereo pure olefins), resulting in a mixture of cis-trans epoxide products. In contrast, the sterically less hindered and electronically different [FeIV(N4Py)(O)]2+ (1) provides only cis-stilbene epoxide. A Hammett study suggests the role of dominant inductive electronic along with minor resonance effect during electron transfer from olefin to 2 in the rate-limiting step. Additionally, a computational study supports the involvement of stepwise pathways during olefin epoxidation. The ferryl bend due to the bulkier ligand incorporation leads to destabilization of both (Formula presented.) and (Formula presented.) orbitals, leading to a very small quintet–triplet gap and enhanced reactivity for 2 compared to 1. Thus, the present study unveils the role of steric and electronic effects of the ligand towards mechanistic modification during olefin epoxidation.
Asymmetric epoxidation of conjugated olefins with dioxygen
Koya, Shota,Nishioka, Yota,Mizoguchi, Hirotaka,Uchida, Tatsuya,Katsuki, Tsutomu
, p. 8243 - 8246 (2012)
A complex situation: Asymmetric epoxidation of conjugated olefins was achieved at room temperature using ruthenium complex 1 as the catalyst and air as the oxidant to give epoxides in up to 95 % ee (see scheme). When the product was acid sensitive, the reaction was carried out at 0 °C under oxygen. Copyright
PALLADIUM(II)-CATALYZED EPOXIDATION OF OLEFINS WITH α-SILYLOXYALKYL PEROXYBENZOATES
Nagata, Ryu,Matsuura, Teruo,Saito, Isao
, p. 2691 - 2694 (1984)
A novel oxygen-atom-transfer reaction from α-silyloxyalkyl peroxybenzoate to olefins by palladium(II) catalyst to give epoxides has been described.
Ruthenium-catalyzed asymmetric alkene epoxidation with tert-butyl hydroperoxide as oxidant
Bhor, Santosh,Tse, Man Kin,Klawonn, Markus,Doebler, Christian,Maegerlein, Wolfgang,Beller, Matthias
, p. 263 - 267 (2004)
A ruthenium-catalyzed asymmetric epoxidation of various olefins using tert-butyl hydroperoxide (TBHP) as the oxidant is reported. By applying ruthenium(pyridinebisoxazoline)-(pyridinedicarboxylate) complexes 1 [Ru(pybox)(pydic), 1] as catalysts, aromatic and aliphatic olefins yielded the corresponding epoxides at room temperature in good to excellent yields and enantioselectivities up to 65% ee. Slow addition of the stoichiometric oxidant significantly improved the yield and the chemoselectivity of the reaction.
Hydrocarbon oxidation catalyzed by manganese and iron complexes with the hexadentate ligand N,N′-di(ethylacetate)-N,N′-bis(2-pyridyl-methyl)- 1, 2-ethanediamine
Zhang, Qiao,Goldsmith, Christian R.
, p. 301 - 306 (2013)
Analogs of recently reported manganese and iron catalysts for alkene and alkane oxidation reactions have been prepared with the potentially hexadentate ligand N,N′-di(ethylacetate)-N,N′-bis(2-pyridylmethyl)-1, 2-ethanediamine (debpn). The Mn(II) and Fe(II) complexes, which were previously found to be hepta-coordinate in the solid state, are capable of catalyzing alkene epoxidation and aliphatic C-H activation reactions, although these activities are inferior to those of related complexes with less coordinating ligands. The hydrocarbon oxidation catalyzed by iron is more severely disrupted. Cyclic voltammetry indicates that the +2 oxidation states for both debpn complexes' metal ions are stabilized by the two additional chelate arms. Product analysis of the C-H activation and olefin epoxidation chemistries suggest that ligand-substrate steric interactions may exert additional inhibitory effects on the reactivity for the manganese catalysts.
Generation and Reactions of Carbene Bearing Unprotected Hydroxy Groups at α-Position
Tomioka, Hideo,Nunome, Yasuo
, p. 1243 - 1244 (1990)
Irradiation of 1,1-dimethyl-2-diazo-2-phenylethanol (1a) either in cyclohexane or in hexene produced 1,1-dimethyl-2-oxo-2-phenylethanol (3a), 2,2-dimethyl-3-phenyloxirane (4a), and 3-phenylbutan-2-one (5a), similarly irradiation of (1a) in methanol gave 1,1-dimethyl-2-methoxy-2-phenylethanol (6a) and 1-methoxy-2-methyl-1-phenylpropene (7a) at the expense of (3a) and (5a), all of which were derived from the (1-hydroxy)cyclohexylphenylcarbene (2b) is also described.
Synthesis of a new chiral N,N,N-tridentate pyridinebisimidazoline ligand library and its application in Ru-catalyzed asymmetric epoxidation
Bhor, Santosh,Anilkumar, Gopinathan,Man, Kin Tse,Klawonn, Markus,Doebler, Christian,Bitterlich, Bianca,Grotevendt, Anne,Beller, Matthias
, p. 3393 - 3396 (2005)
(Chemical Equation Presented) A small ligand library of chiral tridentate N,N,N-pyridinebisimidazolines have been synthesized for the first time. This new class of ligands can be easily tuned and synthesized on multi g-scale. The usefulness of the ligands is shown in the ruthenium-catalyzed asymmetric epoxidation with hydrogen peroxide as oxidant. Excellent yields (>99%) and good enantioselectivities (up to 71% ee) have been obtained for the epoxidation of aromatic olefins.
Electric Birefringences and Molecular Conformations of 2-Aryloxirans in Solution
Aroney, Manuel J.,Calderbank, Kingsley E.,Stootman, Heather J.
, p. 259 - 266 (1983)
Electric birefringence and dipole moment measurements have been made for five aryloxirans as solutes at 298 K.The data are analysed to obtain informations on the preferred solution-state conformations taking into account electronic and steric interactions
