Premium
Cosensitized Electron‐Transfer Photooxygenation of Epoxides. A New Synthesis of Ozonides
Author(s) -
Schaap A. Paul,
Siddiqui Shahabuddin,
Balakrishnan P.,
Lopez Luigi,
Gag Steven D.
Publication year - 1983
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198300060
Subject(s) - photooxygenation , chemistry , electron transfer , photochemistry , electron , organic chemistry , singlet oxygen , oxygen , physics , quantum mechanics
9,10‐Dicyanoanthracene (DCA) and biphenyl (BP) cosensitize the electron‐transfer photooxygenation of epoxides in oxygen‐saturated acetonitrile to form ozonides. These epoxides do not measurably quench the fluorescence of DCA and are, therefore, relatively unreactive under standard photooxygenation conditions with only DCA as sensitizer. However, a dramatic increase in the rate of reaction is observed upon the addition of BP as a non‐light‐absorbing cosensitizer. An investigation of the stereochemistry of the reaction with cis ‐ and trans ‐2,3‐diphenyloxiranes has shown that both epoxides are converted exclusively to the cis ‐ozonide. This striking stereochemical result is consistent with a proposed mechanism involving singlet oxygen addition to an intermediate carbonyl ylide.