6, 6-Dimethyl-2, 4-diphenylcyclohexadienyl Anion and the Failure of Carbanion Homoaromaticity

Laren M. Tolbert, Andrzej Rajca

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Abstract

The title carbanion was generated by methyllithium deprotonation of 6, 6-dimethyl-2, 4-diphenyl-1, 4-cyclohexadiene in tetrahydrofuran. Attempted generation of the identical carbanion using potassium (methylsulfinyl)methide in Me2SO led to cyclopropanation only via isomerization to the 1, 3-diene followed by addition/elimination of (methylsulfinyl)methide anion. Except for modest changes in carbon chemical shifts, the title compound exhibits little thermodynamic driving force toward ring closure or homoaromaticity. The NMR spectra at all temperatures were consistent with a planar nonaromatic anion, again failing to establish the existence of homoaromaticity in such carbanions.

Original languageEnglish (US)
Pages (from-to)4805-4808
Number of pages4
JournalJournal of Organic Chemistry
Volume50
Issue number24
DOIs
StatePublished - Nov 1985

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ASJC Scopus subject areas

  • Organic Chemistry

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