364361-00-2Relevant articles and documents
Kinetics of Cyclopropyl Radical Reactions. 2. Studies on the Inversion of Cyclopropyl and 1-Methylcyclopropyl Radicals and on the Kinetics of Some Addition and Abstraction Reactions of 1-Methylcyclopropyl and 1-Methoxycyclopropyl Radicals
Johnston, Linda J.,Ingold, K. U.
, p. 2343 - 2348 (2007/10/02)
Laser flash photolytic studies have shown that the 1-methylcyclopropyl radical has a reactivity similar to that of the cyclopropyl radical toward styrene, β-methylstyrene, 1,4-cyclohexadiene, CCl3Br, and n-Bu3SnH but that it is more reactive toward CCl4.Chemical trapping with CCl3Br of these two radicals stereospecifically labeled with deuterium yields rate constants for their inversion at 71 deg C of (2.1 +/- 0.8) * 1011 s-1 for c-C3H4.CH3 and ca. 1012 s-1 for c-C3H5..EPR spectra of 13C-labeled radicals confirm that they are nonplanar: a13Cα = 98 and 95.9 G for c-C3H4.CH3 and c-C3H5., respectively.The similar magnitudes of these splittings implies that there is also a similar degree of deviation from planarity.The barrier to inversion is probably ca. 3 kcal/mol for both radicals but the c-C3H5. inverts more rapidly possibly because of hydrogen tunneling. 1-Methoxycyclopropyl is less reactive toward styrene and 1,4-cyclohexadiene than the other two radicals.The EPR spectrum of this radical could not be obtained.
