864066-01-3Relevant academic research and scientific papers
Influence of substitution at the benzylic position on the behavior of stereoisomeric phosphorus compounds as precursors of stabilized carbon-centered radicals
Perez-Prieto, Julia,Galian, Raquel Eugenia,Burgos, Pascual Ona,Minana, Maria Del Carmen Morant,Miranda, Miguel Angel,Lopez-Ortiz, Fernando
, p. 3869 - 3872 (2005)
(Chemical Equation Presented) Efficient benzylic radical formation from benzo[d]-1,2-oxaphospholes has demonstrated their suitability as precursors of stabilized C-centered radicals, a property associated with antioxidant potential. A remarkable stereodifferentiation is observed for alkyl- and aryl-substituted derivatives.
Oxygenation of tert-Butylphenols with an Unsaturated Side Chain
Nishinaga, Akira,Iwasaki, Hitoshi,Shimizu, Tadashi,Toyoda, Yasushi,Matsuura, Teru
, p. 2257 - 2266 (2007/10/02)
Base- and Co(Salpr)-promoted oxygenations of title compounds have been investigated with a view to obtaining further details concerning controlling factors in regioselective O2 incorporation into phenols.In the oxygenation of 4-alkenyl-2,6-di-tert-butyl- and 2-alkenyl-4,6-di-tert-butylphenols (1 and 12), the reactivity of the substrates and regioselectivity in the O2 incorporation may be interpreted in terms of electronic and steric effects of the alkenyl group as well as association effect of the countercation K+ on the transition-state 26 involving a charge transfer from the substrate anion to O2.With 4-alkynyl-2,6-di-tert-butylphenols (21), dioxygen was incorporated exclusively into the ortho position only when the phenolate anion was associated with K+.On the contrary, in the oxygenation of 1 and 12 with Co(Salpr), O2 was incorporated exclusively into the alkynyl side chain, regardless of the nature of the substituent, whereas with 21, O2 incorporation was distributed to both the ortho and the alkenyl side chain.The substituent-dependent regioselectivity in the oxygenation of phenols with Co(Salpr) is because the reactive phenolate-COIII species undergo homolysis to form phenoxy radical-CoII species reversibly, whose oxygenations compete with each other.When the oxygenation of the anionic species predominates, O2 is incorporated into the ortho position, whereas with the radical species the para and side chain oxydations predominate.
