Radical Ion Probes. 8. Direct and Indirect Electrochemistry of 5,7-Di-tert-butylspiro[2.5]octa-4,7-dien-6-one and Derivatives
Results pertaining to the direct and indirect electrochemistry of 5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1a), 1-methyl-5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1b), and 1,1,-dimethyl-5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1c) are reported. Product analyses reveal that reduction of all these substrates leads to cyclopropane ring-opened products; ring opening occurs with modest selectivity leading to the more substituted (stable) distonic radical anion. The direct electrochemistry of these compounds is characterized by rate limiting electron transfer (with α ≈ 0.5), suggesting that while ring opening is extremely rapid, the radical anions do have a discrete lifetime (i.e., electron transfer and ring opening are not concerted). Utilizing homogeneous redox catalysis, rate constants for electron transfer between 1a, 1b, and 1c and a series of aromatic radical anions were measured; reduction potentials and reorganization energies were derived from these rate constants by using Marcus theory.
Repository citation: Phillips, J. Paige; Gillmore, Jason G.; Schwartz, Phillip; Brammer, Larry E. Jr.; Berger, Daniel J.; and Tanko, J. M., "Radical Ion Probes. 8. Direct and Indirect Electrochemistry of 5,7-Di-tert-butylspiro[2.5]octa-4,7-dien-6-one and Derivatives" (1998). Faculty Publications. Paper 1045.
Published in: Journal of the American Chemical Society, Volume 120, Issue 1, January 14, 1998, pages 195-202. Copyright © 1998 American Chemical Society, Washington, D.C..