115648-90-3Relevant articles and documents
Highly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalyst
Zhang, Rui,Yu, Wing-Yiu,Wong, Kwok-Yin,Che, Chi-Ming
, p. 8145 - 8153 (2001)
A dichlororuthenium(IV) complex of 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,2: 5,8-dimethanoanthrance-9-yl] porphyrin, [RuIV(D4-Por*)Cl2] (1), was prepared by heating [RuII-(D4-Po
Stereo- and enantioselective alkene epoxidations: A comparative study of D4- and D2-symmetric homochiral trans-dioxoruthenium(VI) porphyrins
Zhang, Rui,Yu, Wing-Yiu,Sun, Hong-Zhe,Liu, Wei-Sheng,Che, Chi-Ming
, p. 2495 - 2507 (2002)
The mechanism of stoichiometric enantioselective alkene epoxidations by the D4- and D2-symmetric homochiral trans-dioxoruthenium(VI) porphyrins, [RuVI(D4-Por*)O2] (1) and [RuVI(D2-Por*)O2] (2a), in the presence of pyrazole (Hpz) was studied by UV/ Vis spectrophotometry and analysis of the organic products. The enantioselectivity of styrene oxidations is more susceptible to steric effects than to substituent electronic effects. Up to 72% ee was achieved for epoxidation of 3-substituted and cis-disubstituted styrenes by employing 1 as the oxidant, whereas entantioselectivities of only 20-40 % were obtained in the reactions with 2-substituted and trans-disubstituted styrenes. Complex 2a oxidized 2-substituted styrenes to their epoxides in up to 88% ee. Its reactions with transalkenes are more enantioselective (67 % ee) than with the cis-alkenes (40 % ee). Based on a two-dimensional NOESY NMR study, 2a was found to adopt a more open conformation in benzene than in dichloromethane, which explains the observed solvent-dependent enantioselectivity of its reactions with alkenes. The oxidation of aromatic alkenes by the chiral dioxoruthenium(VI) porphyrins proceeds through the ratelimiting formation of a benzylic radical intermediate; the observed enantioselectivity (eeobs) depends on both the facial selectivity of the first C-O bond formation step and the diastereoselectivity of the subsequent epoxide ring closure. To account for the observed facial selection, "side-on" and "top-on" approach transition state models are examined (see: B. D. Brandes, E. N. Jacobsen, Tetrahedron Lett. 1995, 36, 5123).
Enantioselective Epoxidation of Styrene Derivatives by Chloroperoxidase Catalysis
Colonna, Stefano,Gaggero, Nicoletta,Casella, Luigi,Carrea, Giacomo,Pasta, Piero
, p. 1325 - 1330 (1993)
Chloroperoxidase catalysed epoxidation of styrene derivatives by t-BuOOH preferentially gives (R) oxides with ee values between 28 and 68percent.The data support the view of oxygen delivery from the ferryl oxygen directly to the substrate.
Direct electrochemical regeneration of monooxygenase subunits for biocatalylic asymmetric epoxidation
Hollmann, Frank,Hofstetter, Karin,Habicher, Tilo,Hauer, Bernhard,Schmid, Andreas
, p. 6540 - 6541 (2005)
We report the first example of direct electrochemical regeneration of a flavin-dependent monooxygenase for asymmetric epoxidation catalysis. It is shown that electrochemical regeneration of the oxygenase subunit of the multicomponent styrene monooxygenase
Enantioselectivity of a recombinant epoxide hydrolase from Agrobacterium radiobacter
Lutje Spelberg, Jeffrey H.,Rink, Rick,Kellogg, Richard M.,Janssen, Dick B.
, p. 459 - 466 (1998)
The recombinant epoxide hydrolase from Agrobacterium radiobacter AD1 was used to obtain enantiomerically pure epoxides by means of a kinetic resolution. Epoxides such as styrene oxide and various derivatives thereof and phenyl glycidyl ether were obtained in high enantiomeric excess and in reasonable yield. The enantioselectivity (E-value) of the resolution was calculated from progress curves for styrene oxide (E= 16.2) and para- chlorostyrene oxide (E=32.2).
Nitrite-mediated hydrolysis of epoxides catalyzed by halohydrin dehalogenase from Agrobacterium radiobacter AD1: A new tool for the kinetic resolution of epoxides
Hasnaoui, Ghannia,Lutje Spelberg, Jeffrey H.,De Vries, Erik,Tang, Lixia,Hauer, Bernhard,Janssen, Dick B.
, p. 1685 - 1692 (2005)
Halohydrin dehalogenase obtained from Agrobacterium radiobacter AD1, has been tested for the nitrite-mediated ring opening of epoxides. This reaction mainly leads to the formation of unstable hydroxynitrite ester intermediates, which can be further hydrolyzed to the corresponding diols. This conversion proceeds with high enantioselectivity and high regioselectivity towards styrene oxide derivatives. It has been concluded that halohydrin dehalogenase can serve as an attractive alternative to epoxide hydrolases in the preparation of enantiopure epoxides by kinetic resolution.
Enzymatic transformations. Part 58: Enantioconvergent biohydrolysis of styrene oxide derivatives catalysed by the Solanum tuberosum epoxide hydrolase
Monterde, Maria I.,Lombard, Murielle,Archelas, Alain,Cronin, Annette,Arand, Michael,Furstoss, Roland
, p. 2801 - 2805 (2004)
The biohydrolysis of four racemic styrene oxide derivatives has been explored, using the (recombinant) Solanum tuberosum epoxide hydrolase. Interestingly, this enzyme showed a marked tendency to operate a so-called enantioconvergent process, thus affording the corresponding (R)-diol in a nearly quantitative yield and good to excellent ee. We have demonstrated that this is due to the fact that the (S)-enantiomer of these epoxides was preferably attacked at the (benzylic) more substituted carbon atom, whereas the (R)-epoxide was attacked at the (terminal) less substituted carbon atom. The thus obtained meta- and para-chlorostyrene diol derivatives are important building blocks in the synthesis of various biologically active molecules. A nine cycles repeated batch reactor was performed starting from racemic meta-chlorostyrene oxide and afforded a 100% analytical yield (88% preparative) of the corresponding diol, obtained with ees as high as 97%.
Stereospecific biocatalytic epoxidation: The first example of direct regeneration of a FAD-dependent monooxygenase for catalysis
Hollmann, Frank,Lin, Po-Chi,Witholt, Bernard,Schmid, Andreas
, p. 8209 - 8217 (2003)
Catalysis for chemical synthesis by cell-free monooxygenases necessitates an efficient and robust in situ regeneration system to supply the enzyme with reducing equivalents. We report on a novel approach to directly regenerate flavin-dependent monooxygena
A new clade of styrene monooxygenases for (R)-selective epoxidation
Xiao, Hu,Dong, Shuang,Liu, Yan,Pei, Xiao-Qiong,Lin, Hui,Wu, Zhong-Liu
, p. 2195 - 2201 (2021/04/12)
Styrene monooxygenases (SMOs) are excellent enzymes for the production of (S)-enantiopure epoxides, but so far, only one (R)-selective SMO has been identified with a narrow substrate spectrum. Mining the NCBI non-redundant protein sequences returned a new distinct clade of (R)-selective SMOs. Among them,SeStyA fromStreptomyces exfoliatus,AaStyA fromAmycolatopsis albispora, andPbStyA fromPseudonocardiaceaewere carefully characterized and found to convert a spectrum of styrene analogues into the corresponding (R)-epoxides with up to >99% ee. Moreover, site 46 (AaStyA numbering) was identified as a critical residue that affects the enantioselectivity of SMOs. Phenylalanine at site 46 was required for the (R)-selective SMO to endow excellent enantioselectivity. The identification of new (R)-selective SMOs would add a valuable green alternative to the synthetic tool box for the synthesis of enantiopure (R)-epoxides.
Enantiomer Separation of Nitriles and Epoxides by Crystallization with Chiral Organic Salts: Chirality Switching Modulated by Achiral Acids
Hirose, Takuji,Kodama, Koichi,Shimomura, Yuki
, p. 6552 - 6557 (2021/11/16)
Enantiomer separation of nitriles and epoxides by inclusion crystal formation with organic-salt type chiral hosts was achieved. The stereochemistry of the preferentially included nitrile could be switched only by changing the achiral carboxylic acid component. Crystallographic analysis of the inclusion crystals reveals that the hydrogen-bonding networks are controlled by the acidity of the phenol group of the acids, which results in chirality switching.
Peroxygenase-Catalysed Epoxidation of Styrene Derivatives in Neat Reaction Media
Alcalde, Miguel,Arends, Isabel W. C. E.,Hollmann, Frank,Paul, Caroline E.,Rauch, Marine C. R.,Tieves, Florian
, (2019/08/30)
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.
