Hypofluorous acid - acetonitrile

A terminal 1,13 diene with interstitial deka(difluoromethylene) chain is converted to the corresponding diepoxide by repeated reacUon with a very large excess of hypofluorous acid-acetonitrile complex [22](equation 14)... 

Stilbene is also converted into the epoxide and the preparation of the lsO-isomcr 3 in high isotopic purity can also be performed, while 1,1-diphenylethene is transformed to 1.1-di-phenylethane-l,2-diol (4),8 and (T)-stilbene to a mixture of benzophenone9 and //wo-2-fluoro-1.2-diphenylethanol. Fluoro-substituted alkenes can also be converted with a hypofluorous acid/acetonitrile mixture into epoxides 5 in high yield.10... 

Tertiary carbon atoms have been successfully hydroxylated with the mixture of hypofluorous acid/acetonitrile, e.g. formation of 13. and this method has also been used for the introduction of, 80.15... 

The hypofluorous acid/acetonitrile complex has also been used for the oxidation of secondary alcohols and for the Baeyer Villiger oxidation of ketones.24-25... 

The reactivity of a terminal 1,13-diene with an interstitial deca(difluoromethylene) chain 1 is lower towards expoxidation with hypofluorous acid/acetonitrile complex21 due to the electron-withdrawing effect of the perfluoroalkyl chain attached directly to the C = C bond. The diepoxide 2 is obtained by repeated reaction with a very large excess of the oxidizing agent.21... 

A more efficient agent than peroxy compounds for the epoxidation of fluoro-oletins with nonfluonnated double bond is the hypofluorous acid-acetonitrile complex [22] Perfluoroalkylethenes react with this agent at room temperature within 2-3 h with moderate yields (equation 13), whereas olefins with strongly electron-deficient double bond or electron-poor, stencally hindered olefins, for example l,2-bis(perfluorobutyl)ethene and perfluoro-(l-allcylethyl)ethenes, are practically inert [22] Epoxidation of a mixture of 3 perfluoroalkyl-1-propenes at 0 °C is finished after 10 min in 80% yield [22] The tnfluorovinyl group in partially fluonnated dienes is not affected by this agent [22] (equation 13)... 

It is possible that the iodine and base could be generated in the way cited earlier for the oxidation of 2-methylnaphtho-quinone. Fluorine forms a hypofluorous acid-acetonitrile complex when it is passed into wet acetonitrile. This complex has been used to convert olefins, such as undecylenic acid, oleic, and cinnamic acid to the corresponding epoxides in 90% yields.294 The disadvantages of the process are the need to handle the very reactive fluorine and the need to recycle the by-product hydrogen fluoride. 

Though it requires vigorous conditions and is less common than nucleophilic epoxidation, electrophilic epoxidation of aperfluoroalkene is possible with the potent combination of chromic oxide and fluorosulfonic acid, providing another route to hexafluoropropylene oxide (1). As a further example of electrophilic attack, hexa-fluoro Dewar benzene (3) is transformed into either a mono- or a diepoxide by the powerful hypofluorous acid-acetonitrile complex.The fact that the much weaker electrophile MCPBA readily epoxides such electron-deficient alkenes as ethyl pentafiuoromethacrylate (4) suggests that it actually reacts via nucleophilic attack at the [3-carbon. 

---