3-methylenecyclobutyl, cyclopent-3-enyl, and 3-methylenecyclobutylmethyl radicals; absence of homoallylic conjugation

John C. Walton*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

The 3-methylenecyclobiityl radical and the cyclopent-3-enyl radicals show such small e.s.r. hyperfine splittings from the δ- and γ-hydrogens respectively that homoallylic conjugation can be ruled out. Semi-empirical SCF-MO calculations indicated that the through-space interaction of the p-orbital at Ċα with the π-orbitals is negligible because they are >2 Å apart. The 3-methylenecyclobutylmethyl radical rearranges by β-scission to give the 2-allylallyl radicals. The Arrhenius parameters of the rearrangement were determined by kinetic e.s.r. spectroscopy and by study of the reduction of 3-methylenecyclobutylmethyl bromide with tri-n-butyltin hydride. The resonance stabilisation of the rearranged radical causes no significant lowering of the activation energy for β-scission.

Original languageEnglish
Pages (from-to)231-235
Number of pages5
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number2
Publication statusPublished - 1 Dec 1987

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