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Review: Epoxidations of Alkenes with H2O2

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Vitus_Verdegast:
Oxidation Reactions Using Urea-Hydrogen Peroxide; A Safe Alternative to Anhydrous Hydrogen Peroxide

Mark S. Cooper*, Harry Heaney, Amanda J. Newbold, William R. Sanderson

*Department of Chemistry, Loughborough University of Technology, Leicestershire, LE11 3TU, England
 
Synlett (1990) p. 533-535
http://www.geocities.com/phorkys_hecate/0-01210773019689-1077302816.pdf
DOI:10.1055/s-1990-21156

Abstract
Urea-hydrogen peroxide (UHP) alone or in combination with carboxylic anhydrides has been shown to serve as a valuable alternative to anhydrous hydrogen peroxide: the range of substrates oxidised include alkenes (epoxidation), ketones (Baeyer-Villiger reaction), sulphides (to sulphones), nitrogen heterocycles (to N-oxides), and aromatic hydrocarbons (to phenols).

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I'd be glad to type the article up if someone wants, but I can't now as I have very little free time for the moment

Rhodium:
A simple and efficient method for epoxidation of terminal alkenes
C. Copéret, H. Adolfsson and K. B. Sharpless
J. Chem. Soc. Chem. Commun. 1565-1566 (1997) (https://www.thevespiary.org/rhodium/Rhodium/pdf/terminal.epoxidation.mto.pdf)

Abstract
The use of a catalytic amount of 3-cyanopyridine in the methyltrioxorhenium catalysed epoxidation of terminal alkenes with aqueous hydrogen peroxide speeds turnover, which results in the formation of many functionalized epoxides in high yields.

Representative procedure for the epoxidation of terminal alkenes:

A mixture of dec-1-ene (28.0 g, 200 mmol), 3-cyanopyridine (2.08 g, 20 mmol) and MTO (249 mg, 1 mmol) in CH2Cl2 (120 ml) was treated with 40 ml of 30% oxygen evolution ceased (1 h). Following phase separation, the water layer was extracted with CH2Cl2, the combined organic layers were dried over Na2SO4 and concentrated to an oil. Hexane was added to this crude product, and the resulting white precipitate was removed by filtration. The filtrate was concentrated, and the crude colourless oil was distilled to yield 31.4 g of decene oxide (94% yield, 96.5% purity).

In summary, a remarkable, albeit poorly understood, beneficial effect of 3-cyanopyridine on MTO-catalysed epoxidations of terminal alkenes has been established. For this challenging class of substrates, this method of epoxidation could prove to be one of the most convenient because:

(i) it shows good functional group compatibility (wide scope)
(ii) it is mild (i.e. neutral conditions, room temperature)
(iii) it uses a readily available, safe and environmentally friendly oxidizing agent (30% aqueous H2O2)
(iv) it is easy to perform on the scales common (1 to 200 mmol) in the laboratory (no tedious work-up, no by-products).

Rhodium:
Highly selective epoxidation of alkenes and styrenes with H2O2 and manganese complexes of the cyclic triamine 1,4,7-trimethyl-1,4,7-triazacyclononane
Dirk De Vos and Thomas Bein
JCS Chem. Commun. 917-918 (1996) (https://www.thevespiary.org/rhodium/Rhodium/pdf/www.rhodium.ws/pdf/epoxidation-triazacyclononane.pdf)

Abstract
In acetone and at subambient temperatures, manganese complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane catalyse the selective oxidation of many alkenes and styrenes to epoxides with an efficient use of H2O2; the regio- and chemo-selectivity resemble those of manganese–porphyrin catalysts.

Rhodium:
Manganese catalysts in homogeneous oxidation reactions
Jelle Brinksma, Thesis, Univ. Groningen (2002) (http://www.ub.rug.nl/eldoc/dis/science/j.brinksma)

Table Of Contents
* Introduction Oxidation Catalysis
* Manganese Complexes as Homogeneous Epoxidation Catalysts
* In Situ Prepared Manganese Complexes as Homogeneous Catalysts for Epoxidation Reactions with Hydrogen Peroxide
* Homogeneous cis-Dihydroxylation and Epoxidation of Olefins with High Hydrogen Peroxide Efficiency by Mixed Manganese/Activated Carbonyl Systems
* Manganese Catalysts for Alcohol Oxidation
* New Ligands for Manganese Catalysed Selective Oxidation of Sulfides to Sulfoxides with Hydrogen Peroxide
* Conclusions and Future Prospects

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