1763-21-9Relevant academic research and scientific papers
[3,3] Sigmatropic rearrangement of some fluorinated 1,5-hexadienes
Dolbier Jr., William R.,Palmer, Keith W.,Tian, Feng,Fiedorow, Piotr,Zaganiaczyk, Andrzej,Koroniak, Henryk
, p. 1517 - 1532 (2007/10/03)
Fluorine atoms incorporated into 1,5-hexadiene molecule should influence the kinetic as well as the thermodynamic parameters of [3,3] sigmatropic rearrangement (Cope rearrangement). Within few decades is has been documented that this transformation proceeds in a concerted manner, rather than stepwise with some radical intermediates involved. Few new terminally fluorinated 1,5-hexadienes (compounds 3, 5A, 7, 9 and 5B) have been synthesized. The activation parameters of rearrangement have been determined and compared with those known for hydrocarbon analogues. While systems developing chair-like transition states (compounds 3 and 5) showed close similarity with hydrocarbon analogues (compound 1), those developing boat-like transition states (compounds 7, 9 and 5B) may proceed through radical stepwise mechanism. Computational studies of the transition states were carried out, showing that only ab initio methods (MP2 and especially DFT) can give approximate correlation with experimental data, whereas in the case of hydrocarbon analogues even simple semiempirical methods (AM1) were reliable enough to reproduce experimental results.
Synthesis of telechelic dienes from fluorinated α,ω-diiodoalkanes. Part I. Divinyl and diallyl derivatives from model I(C2F4)nI compounds
Manseri, A.,Ameduri, B.,Boutevin, B.,Kotora, M.,Hajek, M.,Caporiccio, G.
, p. 151 - 158 (2007/10/02)
The synthesis of five fluorinated non-conjugated dienes from commercially available α,ω-diiodoperfluoroalkanes is described.Preparation of the fluorinated divinyl derivatives H2C=CH(CF2)nCH=CH2 (n = 2, 4, 6) (2,2, 2,4 and 2,6) was effected by ethylenation of these diiodinated compounds in various ways followed by dehydroiodination in ethanolic potassium hydroxide.Allyl diolefines, H2C=CHCH2(CF2)nCH2CH=CH2 (4,4 and 4,6) were produced by the α,ω-bis-telomerization of allyl acetate followed by deiodoacetoxylation in the presence of zinc.The diacetate precursors 3,4 and 3,6 of the respective diallyls 4,4 and 4,6 were obtained rather than diacetate 3,2 because of the eventual decomposition of α,ω-diiodoperfluoroethane by β-scission.These five fluorinated non-conjugated dienes have been characterized by 1H, 13C and 19F NMR spectroscopy. - Keywords:Telechelic dienes; Fluorinated vinyl dienes; Fluorinated allyl dienes; α,ω-Diiodoperfluoroalkanes; NMR spectroscopy
