21532-81-0Relevant articles and documents
The role of structural effects on the reactions of alkoxyl radicals with trialkyl and triaryl phosphites. A time-resolved kinetic study
Bietti, Massimo,Calcagni, Alessandra,Salamone, Michela
scheme or table, p. 4514 - 4520 (2010/10/02)
(Figure presented) A time-resolved kinetic study on the reactions of alkoxyl radicals with trialkyl and triaryl phosphites ((RO)3P: R = Me, Et, i-Pr, t-Bu; (ArO)3P: Ar = C6H5, 2,4-(t-Bu)2C6H3) has been carried out. In the (RO)3P series, the alkoxyl radicals (cumyloxyl (CumO ·) and benzyloxyl (BnO·)) undergo addition to the phosphorus center with formation of intermediate tetraalkoxyphosphoranyl radicals (R′OP·(OR)3: R = Me, Et, i-Pr, t-Bu; R′ = Bn, Cum). The addition rate constants are influenced by steric effects, decreasing on going from R = Me to R = t-Bu and from BnO · to CumO·. Rate constants for β-scission of the phosphoranyl radicals R′OP·(OR) 3 have also been determined, increasing, for a given alkyl group R, in the order R′ = tert-butyl · reacts with triaryl phosphites (ArO) 3P to give phenoxyl radicals, with rate constants that are influenced to a limited extent by substitution of the aromatic rings. The radical scavenging ability of these substrates is briefly discussed.
