A very efficient system for alkene epoxidation by hydrogen peroxide: catalysis by manganese-porphyrins in the presence of imidazole

Renaud, Jean‐Paul; Battioni, Pierrette; Bartoli, J. F.; Mansuy, Daniel

doi:10.1039/c39850000888

Cited by 135 publications

(36 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As shown in Fig. 9, stereospecific epoxidation of various alkenes are obtained with almost quantitative conversions and yields, and good rates (up to 100 turnovers/min) [98,100]. The H 2 0 2 -Mn(TDCPP)(Cl) -imidazole system may be used for the conversion of alkanes by using a 2 -6-fold excess of H 2 0 z [99].…”

Section: -3 Model Systems Using Alkylhydroperoxides or Hz02mentioning

confidence: 99%

Chemical model systems for drug‐metabolizing cytochrome‐P‐450‐dependent monooxygenases

Mansuy

Battioni

1989

European Journal of Biochemistry

Self Cite

179

View full text Add to dashboard Cite

Monooxygenases are widely distributed enzymes which catalyze dioxygen activation using two electrons and two protons, with the insertion of one oxygen atom from O2 into a substrate and the formation of water (Eqn 1).A great number of these monooxygenases contain a heme protein called cytochrome P-450 which is the site of dioxygen activation. These cytochrome-P-450-dependent monooxygenases are involved in many steps of the biosynthesis and biodegradation of endogenous compounds such as steroids, fatty acids, prostaglandins and leukotrienes. They also play a key role in the oxidative metabolism of exogenous compounds such as drugs and other environmental products allowing their elimination from living organisms. Because of their wide distribution in living organisms and their very important role in biochemistry, pharmacology and toxicology, cytochromes P-450 have been the subject of many studies during the last 20 years. Thus, much is known about the structure and function of cytochromes P-450 (for recent reviews, see [l -41) and more than 60 cytochromes P-450 from various origins have been sequenced [5].However, because of the high molecular mass of cytochromes P-450 (about 50 kDa), it is still difficult to determine the detailed mechanism of substrate oxidations and the nature of the iron intermediates involved in these processes. In particular, it is difficult to determine the molecular structure of the iron-metabolite complexes formed from time to time during the metabolism of some classes of substrates. A possible way to solve these problems is to use biomimetic chemical systems involving iron-porphyrins.In fact, iron-porphyrin model systems for cytochromes P-450 may be used for three main purposes. The first is to determine the nature of the iron complexes involved as intermediates in the catalytic cycle of dioxygen activation and substrate hydroxylation by cytochrome P-450. Model ironporphyrin complexes for all these intermediates except one have been prepared and completely characterized by various spectroscopic techniques. Their structures have been established by X-ray analysis. The spectroscopic characteristics of these model complexes have been found to be very similar to Ahhreviutions. TMP, tetramesitylporphyrin; TPP, meso-tetraphenylporphyriu; TDCPP, tetra-2,6-dichlorophenylporphyrin.those of the corresponding enzymatic complexes and the use of these models has largely contributed to our present detailed knowledge of the catalytic cycle of cytochrome P-450. This first interest of the use of models has been described in previous reviews (see for instance [6 -91) and will not be treated in this article.A second objective of the use of chemical models for cytochromes P-450 is to understand as much as possible about the mechanisms of cytochrome P-450 during these reactions. In particular, the preparation and complete characterization of models for the cytochrome-P-450 -iron -metabolite complexes formed during the metabolism of some drugs or exogenous compounds should allow us to determine the chemical fu...

show abstract

Section: -3 Model Systems Using Alkylhydroperoxides or Hz02mentioning

confidence: 99%

Chemical model systems for drug‐metabolizing cytochrome‐P‐450‐dependent monooxygenases

Mansuy

Battioni

1989

European Journal of Biochemistry

Self Cite

179

View full text Add to dashboard Cite

show abstract

“…[13,16] Dinuclear triazacyclononane and pyridylamine complexes were also shown to promote alkene epoxidation in the presence of H 2 O 2 . [13] Most of these oxygen transfer processes have been proposed to proceed through a high-valent oxo-manganese moiety, Mn(V) = O, stabilized by electron density donation from ligands containing both s-and p-electron systems.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Epoxidation of Alkenes by the Manganese Complex of a Reduced Porphyrinogen Macrocycle

et al. 2012

View full text Add to dashboard Cite

The present paper details the first application of a fully reduced meso-octamethylporphyrinogen macrocycle as an effective ligand for simple operative manganese-catalyzed alkene epoxidation. The efficiency of the novel catalyst was determined in the presence of various oxidants, apical ligands and acidic/basic additives. Higher reactivity was found in favour of electron-rich alkenes, whereas an electron-deficient conjugated alkene appeared as a poor substrate in the screening. Sulfur additives were active as apical ligands, whereas nitrogen-containing additives influenced the reactivity only moderately. cis-Stilbene and 3b-acetoxy-5-cholestene were epoxidized in a stereoselective manner. The X-ray structures of the new manganese complexes were determined and showed a rigid planar coordination geometry of the saturated macrocyclic ligand to the metal centre.

show abstract

“…Reasonably stable active complexes were found, allowing the use of various oxygen donors [1][2][3][4]. Studies and attempted rationalisations for the role of substituents at the porphyrin periphery on the catalytic activity can also be found in the literature, involving the introduction of halogens or bulky groups in the mesophenyls [5,6] or halogenation of the pyrrolic positions [7,8] of the basic meso-tetraphenylporphyrin skeleton. In specific cases elaborate porphyrin structures for the catalyst were also used [9,10].…”

Section: Introductionmentioning

confidence: 99%

The manganese complex of 2,3,7,8,12,13,17,18-octaphenylporphyrin as epoxidation catalyst

Sobral

Gonsalves

2001

J. Porphyrins Phthalocyanines

View full text Add to dashboard Cite

show abstract

A very efficient system for alkene epoxidation by hydrogen peroxide: catalysis by manganese-porphyrins in the presence of imidazole

Cited by 135 publications

References 1 publication

Chemical model systems for drug‐metabolizing cytochrome‐P‐450‐dependent monooxygenases

Chemical model systems for drug‐metabolizing cytochrome‐P‐450‐dependent monooxygenases

Catalytic Epoxidation of Alkenes by the Manganese Complex of a Reduced Porphyrinogen Macrocycle

The manganese complex of 2,3,7,8,12,13,17,18-octaphenylporphyrin as epoxidation catalyst

Contact Info

Product

Resources

About