115-42-4Relevant articles and documents
Acid catalysis vs. electron-transfer catalysis via organic cations or cation-radicals as the reactive intermediate. Are these distinctive mechanisms?
Rathore, Rajendra,Kochi, Jay K.
, p. 114 - 130 (2007/10/03)
Proton transfer to aromatic and olefinic donors (D) leads to the facile interchange of transient carbocations (DH+) and cation-radical (D+.). The same types of cation and cation-radical are reactive intermediates in the acid catalysis and the electron-transfer catalysis of such organic transformations as benzylic coupling, epoxide/pinacol rearrangements and cis-trans isomerization of stilbenes when they are both carried out under otherwise identical reaction conditions. However, the rapid exchange of diamagnetic cations and paramagnetic cation-radicals blurs the traditional view of separate electrophilic and homolytic processes, and rigorous experimental evidence is required to establish whether acid catalysis and electron-transfer catalysis actually represent distinct mechanistic categories. Acta Chemica Scandinavica 1998.
Photoinduced Electron Transfer Reaction. Part 3. 9,10-Dicyanoanthracene-sensitized Photo-oxidation of Electron-rich Stilbene Oxides
Futamura, Shigeru,Kusunose, Shosaku,Ohta, Hiroyuki,Kamiya, Yoshio
, p. 15 - 19 (2007/10/02)
The 9,10-dicyanoanthracene (DCA)-sentisized photo-oxygenation of the electron-rich stilbene oxides (1) gives the ozonides (2) almost quantitatively.The fluorescence of DCA is quenched by (1) at a diffusion-controlled rate and the above reaction is quenched by polymethoxybenzenes which indicates that an electron transfer mechanism is involved.The quantum yield for ozonide formation varies from 0.6 for trans-2-(4-methoxyphenyl)-3-phenyloxirane (1d) to 2.4 for trans-2,3-bis(4-methoxyphenyl)-2,3-diethyloxirane (1h), suggesting a duplex reaction mechanism such as photo-oxygenation by superoxide and a Barton mechanism after the initial electron transfer from the epoxides (1) to the excited singlet state of DCA.
