Clocking Tertiary Cyclopropylcarbinyl Radical Rearrangements
| Autor: | Engel, Paul S., He, Shu-Lin, Banks, J. T., Ingold, K. U., Lusztyk, J. |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | The Journal of Organic Chemistry. 62:5656-5656 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/jo974012n |
| Popis: | Three independent methods have been employed to estimate the rate constant, k1, for ring-opening of the 2-cyclopropyl-2-propyl radical, 1, at room temperature. These three estimates are based on chemical trapping of 1 and the ring-opened 4-methylpent-3-ene-1-yl radical by thiophenol (k1 = (1.65 ± 0.41) × 107 M-1 s-1), 9-azabicyclo[3.3.1]nonane-N-oxyl (k1 = (1.76 ± 0.34) × 107 M-1 s-1) and 2,2,6,6-tetramethylpiperidine-N-oxyl (k1 = (2.1 ± 0.4) × 107 M-1 s-1) and absolute rate constants for nonrearranging radicals structurally related to 1. The mean value for k1 ((1.84 ± 0.4) × 107 M-1 s-1) should be used when 1 is employed as a tertiary alkyl free radical clock at ambient temperatures. |
| Databáze: | OpenAIRE |
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