Cosensitization by 9,10-dicyanoanthracene and biphenyl of the electron-transfer photooxygenation of 1,1,2,2-tetraphenylcyclopropane

Electrochemical Aerobic Oxidation of Aminocyclopropanes to Endoperoxides

“…[1][2][3] Among these, very few examples involve aminocyclopropanes. The transformation of secondary cyclopropylamines into a-amino endoperoxides by autocatalytic aerobic oxidation was reported by Wimalasena et al a few years ago.…”

Photoinduced electron transfer oxygenations

“…Contrarily to the observations of Schaap's group [103], the course of these reactions is not modified upon the addition of additives, yielding, at different times, a similar mixture of isomeric 1,2-dioxolanes (95-99%), along with traces of by-products directly arising from the subsequent electron-transfer oxidation on the major reaction products, i.e., 80a-d. These results strongly suggest that, in the DCA-sensitized reactions on 1,2-cycloalkanes, the radical ion pairs are produced spontaneously upon excitation of DCA specifically in polar solvents.…”

“…As an example, 1,1,2,2-tetraphenylcyclopropane 74a (E °x= 1.48 V vs SCE) quenchs 1DCA* more efficiently than BP. Notwithstanding this, the rate of photooxygenation of 74a can be increased by more than a factor of 10 by addition of an equimolecular amount of BP [103]. More interestingly, the reaction course is also modified by addition of BP.…”

“…On this ground, DCA was found a suitable sensitizer to induce the photooxygenation of a great variety of organic compounds such as alkenes [84,[94][95][96][97][98], alkynes [99,100], sulfides [84,98,101], dienes [84], sulfoxides [102], cycloalkanes [103,104], cycloalkenes [105,106], epoxides [107,108], aziridines [109], allenes [110], dioxenes [111], p-dioxins [111,112], aromatic substrates [113], tertiary amines [114], and of great interest from the mechanistic point of view, sterically hindered olefines [97,[115][116][117].…”

“…More interestingly, the reaction course is also modified by addition of BP. In fact, the DCA-sensitized photooxygenation of cycloalkanes, and for example of 74 a, leads to a mixture of hydroperoxide 75 a and benzophenone together with minor amounts of the corresponding 3,3,5,5-tetraphenyl-l,2-dioxolane 76a, a major reaction product in the BP-cosensitized reaction [103,109]:…”