126281-30-9Relevant academic research and scientific papers
Kinetics of reactions of cyclopropylcarbinyl radicals and alkoxycarbonyl radicals containing stabilizing substituents: Implications for their use as radical clocks
Beckwith, Athelstan L. J.,Bowry, Vincent W.
, p. 2710 - 2716 (1994)
The rate constants for rearrangement of α-substituted cyclopropylcarbinyl radicals have been measured by nitroxide radical-trapping (NPT). Those bearing methyl, dimethyl, or cyclopropyl substituents undergo ring opening 2-3 times more slowly than does cyclopropylmethyl radical, but the reaction is essentially irreversible under the conditions used. Phenyl and tert-butoxycarbonyl α-substituents retard the rate of ring opening more strongly and enhance the rate of ring closure of the corresponding substituted but-3-enyl radicals. Thus for c-C3H5CHPh at 60°C, kring open = 5.4 × 105 s-1, kring close = 1.5 × 107 s-1, and the equilibrium favors the ring closed form (Kequil = 0.04). The implications of the possible reversibility of the ring opening of substituted cyclopropylcarbinyl radicals for cyclopropane probe studies of metal hydride reduction and other chemical/biochemical reactions are assessed. Most of the cyclopropylcarbinyl radicals were generated from tert-butyl peroxyglyoxalates [ROC(O)CO3But) via alkoxycarbonyl radicals (ROC?O). This method allowed the determination of the rate constants for decarboxylation of ROC?O when R is t-Bu, PhCH2, c-C3H5CMe2, c-C3H5CHMe, (c-C3H5)2CH, or c-C3H5CHC6H5.
Evidence for Reversible Ring-opening of the α-Cyclopropylbenzyl Radical
Bowry, Vincent W.,Lusztyk, Janusz,Ingold, K. U.
, p. 923 - 925 (1990)
Kinetic absorption spectroscopy, EPR, and tributylstannane product data indicate that the α-cyclopropylbenzyl radical (1a) undergoes reversible ring-opening to the 4-phenylbut-3-enyl radical (2a) and that equilibrium favours the ring-closed form, (1a).
