73743-44-9Relevant articles and documents
Radical Addition to Alkynes: Electron Spin Resonance Studies of the Formation and Reactions of Vinyl Radicals
Foxall, James,Gilbert, Bruce C.,Kazarians-Moghaddam, Hira,Norman, Richard O. C.,Dixon, William T.,Williams, Gareth H.
, p. 273 - 278 (2007/10/02)
The e.s.r. spectra are described of a series of vinyl radicals XRC=CR. (R=CO2H, CO2(1-)) formed by the addition of a variety of alkyl, hydroxyalkyl, and aryl radicals (X) to butynedioic acid and the corresponding dianion.For the reaction between Pri. and HO2CCCO2H, k is estimated as ca. 2*106 dm3 mol-1 s-1.In acid solution the first formed vinyl radicals react with more alkyne to give further vinyl radicals XRC=CR-CR=CR. which, if structurally suited, undergo a 1,5-shift to give pentadienyl radicals.The spectra of the latter .HCO2H from .CH3 and butynedioic acid> indicate there to be considerable twisting around the C(3)-C(4) bonds so that conjugation is reduced compared to that in the fully conjugated unsubstituted pentadienyl radical.