Sensitized photooxygenation of 6, 6-diethoxyfulvene (1) and 6, 6-(ethylenedithio)fulvene (9) at —78 °C afforded diethoxyfulvene endoperoxide 2 and (ethylenedithio)fulvene endoperoxide 10, respectively, as primary products. Further irradiation resulted in formation of the novel bisperoxides 3 and 11 from [2 + 2] cycloaddition of 1O2 to the exocyclic double bond of the corresponding endoperoxides. The initial endoperoxides were characterized by NMR at low temperature and underwent a variety of chemical transformations to give highly oxygenated cyclopentane derivatives. In contrast, photooxygenation of 6, 6-dipiperidinofulvene (16) and 6-(dimethylamino)fulvene (17) did not lead to chemical reaction; these compounds physically quench 1O2 with rate constants on the order of 108 M-1 s-1.
ASJC Scopus subject areas
- Organic Chemistry