Epoxidations with oxygen

Table 3 KinetComparison of Olefin Epoxidation with Oxygen and Peroxides as Oxidant 16 19 ...

The primary type of epoxide reaction remains the nucleophilic ring-opening reaction. The ring opening reactions of epoxides with oxygen nucleophiles represents an important method for the synthesis of differentially O-substituted 1,2-diols. The ring opening of epoxides with... 

Cydooctene has been epoxidized with oxygen using a manganese porphyrin as catalyst (equation... 

Reaction medium. By virtue of its attributes supercritical carbon dioxide deserves its increasing applications as a reaction medium in synthesis. These include epoxidation" with oxygen and PhCHO, rhodium-catalyzed hydroboration, Pd(0)-catalyzed 1,4-hydroarylation of enones" and Heck reaction in the presence of Pd-C," carbonylation of aryl halides, Glaser coupling of 1-alkynes (mediated by CuCy using a solid ba.se (NaOAc)," as well as seandium(III) perfluorooctanesulfonate-catalyzed Diels-Alder and hetero-Diels-Alder reaetions. ... 

For epoxidation of enones and related s > l> leucine exerts desirable effects, yieldini Fnone epoxidation with oxygen in i -[Pg.84]

For epoxidation of enones and related substances with alkaline hydrogen peroxide, polyleucine exerts desirable effects, yielding products with greater than 90% ee. " Enone epoxidation with oxygen in the presence of EtjZn and R,R)-N-methylpseudoephedrine is also satisfactory. 

Reactions of epoxides with oxygen-containing nucleophiles 06ZOR327. 

Expoxidation of alkenes. In the presence of this complex, alkenes undergo epoxidation with oxygen (oxidant) and cyclic ketones as reductant. The most useful reductant is 2-methylcyclohexanone. Yields are 80% for trisubstituted or exo-terminal alkenes. 

The direct epoxidation of olefins can be carried out with oxygen, per compounds, or alkaline hydrogen peroxide. In contrast to the above-mentioned processes, epoxidation with peracids occurs on the less sterically hindered side without Walden inversion. Direct epoxidation with oxygen... 

Ito, Y. and Matsuura, T, The reaction of epoxides with oxygen-transfer reagents, /. Chem. Soc., Perkin Trans. 1, 1871,1981. 

Valuable products are produced from the oxidation of both ethylene and propylene (Figs. 1 and 2). Ethylene is epoxidized with oxygen in the vapor phase over a silver catalyst, and propylene is epoxidized with an alkyl hydroperoxide in the liquid phase using a molybdeniim catalyst system. Vinylic oxidation products or their stable isomers, including acetaldehyde, acetone, and vinyl acetate, have been manufactured by a series of related catalytic reactions. These reactions occur either in solutions of palladium complexes or on the surfaces of supported palladium catalysts. Bismuth molybdate is an effective catalyst for allylic oxidations of propylene, which are of paramount importance to the chemical industry. Propylene is oxidized in the vapor phase to give acrolein for acrylic acid manufacture or, in the presence of ammonia, to give acrylonitrile. Second- and third-generation catalysts,... 

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