CHARACTERIZATION OF A HYPERSENSITIVE PROBE FOR SINGLE-ELECTRON TRANSFER TO CARBONYL-COMPOUNDS

The radical anion generated from 1,1 hyl-5,7-di-tert-butylspiro[2.5]oc ta-4,7-dien-6-one (1) undergoes facile ring opening yielding both the 3-degrees and 1-degrees distonic radical ions in a ratio of 9: 1 with a rate constant greater-than-or-equal-to 10(7) s-1 (relief of cyclopro pane ring strain and the generation of an aromatic ring provide the th ermodynamic 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 a s a viable substrate for use as a hypersensitive SET probe in mechanis tic studies.