50428-63-2Relevant academic research and scientific papers
Substituent effects on regioselectivity in the autoxidation of nonconjugated dienes
Tallman, Keri A.,Rector, Christopher L.,Porter, Ned A.
supporting information; experimental part, p. 5635 - 5641 (2009/09/25)
Free radical oxidation of several 1,4-dienes was carried out in the presence of variable concentrations of R-tocopherol to investigate the effect of diene structure on product distribution. Oxidations carried out at low tocopherol concentration gave only C-1 and C-5 conjugated diene hydroperoxides, while higher concentrations of the antioxidant resulted in formation of substantial amounts of the nonconjugated C-3 diene hydroperoxide. Increasing size of the substituents at C-1 and C-5 of the diene favors kinetic products arising from oxygen addition at the nonconjugated position, C-3, of the pentadienyl radical intermediate. Substituents at C-1 or C-5 of the pentadienyl radical also have a significant effect on the regioselectivity of the conjugated diene hydroperoxides formed, larger substituents directing oxygen addition to the pentadienyl radical at the site of least steric hindrance. This trend is also observed in oxidations of ω-3 and ω-6 linolenate fatty acid esters. Groups atC-1 and C-5 of the diene can influence product distribution based upon (a) steric demand in the oxygen-radical reaction and (b) the influence o f substituents on the rearrangement of the C-3 peroxyl radical to give conjugated diene products.
Stereochemistry of Olefin and Fatty Acid Oxidation. Part 1. Autooxidation of Hexene and Hepta-2,5-diene Isomers
Frankel, Edwin N.,Garwood, Robert F.,Vinson, John R.,Weedon, Basil C. L.
, p. 2707 - 2714 (2007/10/02)
The stereochemistry of the autooxidation of hex-1-ene, cis- and trans-hex-2-ene, cis- and trans-hex-3-ene, and of the three geometrical isomers of hepta-2,5-diene, has been determined by the reduction of the hydroperoxides produced and analysis of the resulting allylic alcohols.The relative proportions of the isomeric hydroperoxides are explicable in termes of the conformation of the parent olefins which are capable of giving delocalised radicals on hydrogen abstraction.
