Oxidation of Alkenes, using Peroxides

Oxidation of Alkenes to Oxirans, using Peroxides. The peroxide (15 R = OOH) is a useful oxidant for a number of alkenes, giving epoxides in good to moderate yields and generating (15 R = OH). The reactivity of this peroxide is two orders of magnitude lower than that of peroxyacetic acid but at least one order of magnitude greater than that of a-peroxy-esters and -nitriles. Its selectivity relative to the structure of the alkene is similar to that for peroxyacetic acid. 

4-vinylcyclohexene with only 4% total yield of other possible mono- and di-epoxide products. 

Base-catalysed epoxidation of norandrostenone (19), using H2O2 in methanol, produced exclusively the j3-epoxide in the A ring. It was suggested that the conformations of the A ring were such that the hydroperoxide group attached at the 5a- or 5j3-positions could attain an axial confirmation, cis-Cyclo-octene oxide (20) has been prepared in 60% yield by epoxidation of 

A number of different catalysts have been used in the epoxidation of monoterpenes with t-butyl hydroperoxide and the conditions optimized. While oxidation of a-pinene in the presence of V(acac)3 gave ds-epoxide (4.4%), campholenic aldehyde was also obtained in the presence of Mo(CO)e. 

line-broadening method was applied to the determination of the kinetic parameters of the exchange reactions of cumene hydroperoxide, cumyl alcohol, and cyclohexene in the co-ordination sphere of the complex H2 [Mo204(C204)2(H20)2] -4H20 (CH3)2C0. The results revealed that the first stage of both the decomposition of the hydroperoxide and the epoxidation reaction is the formation of an intermediate compound between a molybdenum(v) complex and the hydroperoxide. 

Oxidation of Alkenes to Oxirans, using Peroxides. Two reviews in this area have been published, one dealing with new methods for the catalytic epoxidation of alkenes using hydrogen peroxide and the other with selective oxidation of alkenes and alkynes with t-butyl hydroperoxide.  

The direct oxidation of alkenes to oxirans by hydrogen peroxide is, of course, only possible when a catalyst is used. In the past the main choice of catalyst has been oxides of the metals of Groups 5a, 5b, 6a, or 6b. In 1978, however. Sharpless put the use of arylseleninic acids as catalysts on a firm practical footing.Using the nitrophenylseleninic acids (25 R = H, R = NO2) and (25 R = R = NO2), 95 % preparative yields of cyclo-octene oxide were obtained from the alkene in CH2CI2 with 30% H2O2. 

Another new group of catalyst systems for direct epoxidations by hydrogen peroxide is the arsonated polystyrenes. Using a triphasic system of CHCI3, 30% H2O2, and the catalyst (in the form of beads), slow but selective epoxidations of 

Orekhov and B. M. Rudenko, Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol., 1979, 22, 

Sorokin, E. L. Gershanova, and Yu. V. Stukalov, Deposited Document, 1978, VINITI 3841 

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