Revised structure of a purported 1,2-dioxin: A combined experimental and theoretical study

Eric Block, Zhixing Shan, Richard S Glass, Jürgen Fabian

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3,6-Bis(p-tolyl)-1,2-dioxin (1g) was suggested by Shine and Zhao as a product in an electron-transfer (ET) photochemical reaction. This photoproduct is instead shown to be (E)-1,4-di-p-tolylbut-2-ene-1,4-dione ((E)-4a). Ab initio and DFT calculations indicate that ring-closed 1,2-dioxin is thermodynamically far less stable than open-chain but-2-ene-1,3-dione. These calculations indicate that (E)-4a is formed via the cation radical of 1g, which sequentially isomerizes to a novel (σ-radical with an O,O 3e bond [(Z)-4a]+•, undergoes ET to give (Z)-4a, and then photoisomerizes to (E)-4a.

Original languageEnglish (US)
Pages (from-to)4108-4111
Number of pages4
JournalJournal of Organic Chemistry
Issue number10
Publication statusPublished - May 16 2003


ASJC Scopus subject areas

  • Organic Chemistry

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