Characterization of a ‘hypersensitive’ probe for single electron transfer to carbonyl compounds

Abstract

The radical anion generated from 1,1-dimethyl-5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1) undergoes facile ring opening yielding both the 3° and 1° distonic radical ions in a ratio of 9 : 1 with a rate constant ≥10⁷ s^–1(relief of cyclopropane ring strain and the generation of an aromatic ring provide the thermodynamic driving force for this rearrangement), the facility of C–C bond cleavage in this radical anion and the observed electrochemistry are reminiscent of the reductive cleavage of carbon–halogen bonds in alkyl and benzylic halides: on the basis of these results, 1 emerges as a viable substrate for use as a hypersensitive SET probe in mechanistic studies.