| Résumé | The title radical, 5, has been generated by hydrogen atom abstraction from spiro[2.5]octa-4,6-diene (4). The radical could not be observed by EPR spectroscopy even at temperatures as low as 100 K. Instead, the EPR spectrum of the cyclopropyl ring-opened product was obtained, 2-phenylethyl (6). However, 5 was identified by using optical detection methods by means of its absorption and fluorescence at ca. 560 nm, which is a characteristic of cyclohexadienyls. The rate constant for H atom abstraction from 4 by tert-butoxyl was measured at 295 K, and approximate Arrhenius parameters for the 5 to 6 rearrangement have been estimated. The hydrocarbon 4 is remarkably resistant to the thermodynamically favored, radical induced rearrangement to ethyl benzene. © 1980 American Chemical Society. |
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