Concerning zwitterionic peroxide or diradical intermediates in the singlet oxygen-olefin ene reaction

✍ Scribed by Sr.M.Bellarmine Grdina; M. Grdina; M. Orfanopoulos; L.M. Stephenson

• Publisher: Elsevier Science
• Year: 1979
• Tongue: French
• Weight: 183 KB
• Volume: 20
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)86586-2

✦ Synopsis

Arguments are presented which show that zwitterionic or diradical intermediates in the singlet oxygen-olefin ene reaction would lead to a prediction that geminal groups would be competitive in the C-H abstraction reaction. Isotope effect data available from previous studies clearly show that such is not the case. Thus, these intermediates are inappropriate as a general description of this reaction.

The mechanism of the singlet oxygen-olefin ene reaction continues to be a controversial issue. Recent experimental observations and theoretical calculations have reintroduced biradicalz or zwitterions as intermediates and we wish to comment on the appropriateness of these species in this reaction. Conia's 1977 report' of regioselectivity in the photooxygenation of vinyl ethers prompted Goddard's proposal in 1978 of a biradical intermediate 4, with a conformational preference due to an anomeric effect. Conia's experiments can now be recognized as the first of a general set of