Electron transfer ring opening

Isoxazolones, electron transfer ring opening reactions of 89YGK629. 

Albini, A. and Arnold, D. R., The photosensitized (electron transfer) ring opening of aryloxiranes. 

As with other hydroperoxides, hydroxyaLkyl hydroperoxides are decomposed by transition-metal ions in an electron-transfer process. This is tme even for those hydroxyaLkyl hydroperoxides that only exist in equiUbrium. For example, those hydroperoxides from cycHc ketones (R, R = alkylene) form an oxygen-centered radical initially which then undergoes ring-opening -scission forming an intermediate carboxyalkyl radical (124) ... 

Reductive ring opening of epoxides in radical reactions in presence of titanocenes as electron transfer catalysts 98SL801. 

Electron transfer to vinylaziridines results in ring-opening reactions, yielding allyl amines. Treatment of 268 with SmI2/DMEA (N,N-dimethylethanolamine) provided allyl amine 269 as a 2 1 mixture of olefmic isomers in 88% yield (Scheme 2.66) [97]. 

Scheme 2.66 Ring-opening reactions resulting from electron transfer.

The ESR spectrum of the furan radical anion indicates that the Cem-0 bond is ruptured in the electron transfer process whereby the oxygen atom acquires the negative charge and the C-2 end of the open ring possesses a free radical character ... 

Electron-transfer activation. The photoinduced electron-transfer activation of the [DBC, TCNE] complex generates the DBC+ cation radical, which undergoes a fast electrocyclic ring opening, i.e.,... 

Takahashi et al. (1996) described another case of cation-radical cycloreversion. Benzocyclobu-tenols undergo ring opening induced by electron transfer to generate quinodimethide intermediates, which then tautomerize to benzophenones. The reaction proceeds on photoirradiation in the presence of tetracyanoanthracene (X > 350 nm). Yields (based on NMR (proton) analyses) are quantitative... 

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