380-57-4Relevant articles and documents
1-Vinyl-1,2,2,3,3-pentafluorocyclopropane: An extraordinarily rapid vinylcyclopropane rearrangement
Smart, Bruce E,Krusic, Paul J,Roe, D.Christopher,Yang, Zhen-Yu
, p. 199 - 205 (2007/10/03)
The synthesis of 1-vinyl-1,2,2,3,3-pentafluorocyclopropane (1) and the kinetics of its thermal, unimolecular rearrangement to 1,4,4,5,5-pentafluorocyclopentene (2) are reported. Kinetic data were obtained by gas-phase 19FNMR at 80-120 °C, and the activation parameters for the rearrangement of 1 to 2 are: ΔG?(100 °C) = 28.7 kcal/mol, ΔH? = 26.7 kcal/mol, and ΔS? = -5.5 eu (log A = 12.7, Ea = 28.4 kcal/mol). Vinyl(pentafluorocyclopropane) (1) with a half-life of only 38 min at 110 °C, is one of the most thermally labile vinylcyclopropanes known. The isomeric E- and Z-1-propenyl-1,2,2,3,3-pentafluorocyclopropanes (3) similarly have relatively low activation parameters: ΔG?(E) ? 28.5 kcal/mol and ΔG?(Z) ? 31.1 kcal/mol. A favorable, polar biradical transition state for rearrangement is proposed to account the exceptional reactivity of these alkenyl pentafluorocyclopropanes.