Nonconjugated dienes epoxidation

A similar method has been used for the epoxidation of nonconjugated diene 3, prepared from perfluoro(2,2-dimethyl-l, 3-dioxole).104... 

In the epoxidation of olefins not bearing a complexing group, there is not a great difference in stereoselectivity in comparison with the peracids. The c/s-oxirane is formed from cis-butene-2 and the trans-oxirane from trans-butene-2. Due to steric hindrance, regioselectivity may be observed for nonconjugated dienes. °° ° In terpenes, the attack takes place from the less hindered side. Double bonds in bridged cyclic systems have an effect on the reaction rate. ... 

Regio- and stereoselectivity are important considerations in the epoxidation of more complex olefin substrates. In this context it is important to distinguish between two types of effect those which are attributable to electronic and steric factors inherent in the substrate and those which are derived from a particular property of the reagent. An example of the former is the difference in reactivity of double bonds in nonconjugated dienes due to increasing alkyl substitution, as illustrated with limonene (eq. (13)) [31]. 

Epoxidation of various acyclic and cyclic perfluorinated dienes is accomplished with an aqueous hypohalogenitc and acetonitrile as a cosolvent. The reactivity of a C = C bond toward this reagent is enhanced by the presence of the trifluoromethyl group. This activating effect is nicely illustrated by perfluoro(l-methylcyclohexa-l,4-diene), which reacts smoothly with sodium hypochlorite to give a diepoxide 11 in 58% yield,73 while the oxidation system failed for perfluorocyclohexadienes. Nonconjugated perfluorocyclohepta-1,4-diene (12) is oxidized to the corresponding diepoxide 13 by sodium hypobromite.74... 

---