Properties of small ring free radicals. I. Thermal decompositions of α-substituted cyclopropyl percarboxylates
✍ Scribed by R.A. Wolf; W. Rozich
- Book ID
- 104213629
- Publisher
- Elsevier Science
- Year
- 1975
- Tongue
- French
- Weight
- 252 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Several experimental techniques have evolved to differentiate between two possible mechanisms of the thermal decomposition of oeroxv esters. These two mechanisms, the concerted and the non-concerted (Scheme I), have been investi-1 aated bv studvinq activation parameters , the effect on rates of decomposition by changing solvent viscositv2, deuterium isotope effects3, volumes of activationl, 5 scramblinq of isotopic O-18 labeled carbonvl oxvsen , and Hammett siqma-Scheme I Concerted: Q-C03~Bu------+ 9. + CO + -0tBu 2 -Non-Concerted: %-C03tBu ____) R-C?,*+ .r)tBu-R*+C02+'"tBu rho correlations 6 of many series of peroxy esters. From these studies has come solid evidence that the rates of peroxv ester decomposition (the rate of decarboxylation in the non-concerted mechanism) are hichlv deuendent on such properties of the peroxides as conjugation, inductive polar and hybridization 7 effects.