Photoinduced electron transfer oxiranes

Redox photosensitization or co-sensitization by aromatic hydrocarbons has been utilized for enhancement of the efficiency of photoinduced electron transfer reactions. For example, the efficiency of the 9,10-dicyanoanthracene-sensitized photooxygenation of 1,2-diphenyloxirane in acetonitrile is enhanced appreciably by adding biphenyl as a co-sensitizer, giving 3,5-diphenyl-1,2,4-trioxolane in good yield [31-32]. This photoreaction does not take place in the absence of biphenyl. Schaap proposed that in this photoreaction the primary electron transfer reaction occurs from biphenyl (BP) to DCA to produce biphenyl radical cation BP and DCA . The secondary electron transfer from the oxirane to BP produces BP and the radical cation of the oxirane which is converted into the trioxolane (Scheme 5). 

Photoinduced Electron Transfer Reactions of Oxiranes and Epoxy Ketones... 

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