197356-81-3Relevant articles and documents
Synthesis of Trifluorovinyl Ethers Incorporating Functionalized Hydrocarbon Ether Groups: Insight into the Mechanism of Trifluorovinyl Ether Formation from Trimethylsilyl 2-Alkoxy-2,3,3,3-tetrafluoropropionates
Lousenberg, Robert D.,Shoichet, Molly S.
, p. 7844 - 7849 (1997)
Novel trifluorovinyl ethers (TFVEs, ROCF=CF2), where R is an oligoether, were synthesized from the corresponding sodium alkoxide and hexafluoropropene oxide.The sodium alkoxide ring opened hexafluoropropene oxide at the more highly substituted carbon (C2) to give 2-alkoxy-2,3,3,3-tetrafluoropropionic acid ester incorporating 2 equiv of the alcohol, ROCF(CF3)CO2R.Hydrolysis of the ester and reaction of the resulting sodium 2-alkoxy-2,3,3,3-tetrafluoropropionate with chlorotrimethylsilane gave the trimethylsilyl 2-alkoxy-2,3,3,3-tetrafluoropropionate, ROCF(CF3)CO2Si(CH3)3.Gas phase vacuum thermolysis of the trimethylsilyl ester at 140-150 deg C gave the corresponding TFVEs in 55-63percent yields.Thus, 1--1,2,2-trifluoroethene and 1--1,2,2-trifluoroethene were synthesized from 2-(2-ethoxyethoxy)ethanol and 2-(2-tert-butoxyethoxy)ethanol, respectively.Interestingly, thermolysis of sodium or potassium 2-alkoxy-2,3,3,3-tetrafluoropropionates resulted in negligible to low yields of TFVEs.1 For example, thermolysis of sodium 2--2,3,3,3-tetrafluoropropionate gave a trifluoroacetate ester, 2-(2-ethoxyethoxy)ethyl trifluoroacetate.Variable temperature 19F NMR spectroscopy of trimethylsilyl 2--2,3,3,3-tetrafluoropropionate suggests that an equilibrium exists between two structural conformations of these trimethylsilyl esters: one in which there is an intramolecular "interaction" of silicon with fluorine and one in which there is no silicon-fluorine interaction.This interaction may affect the outcome of the trimethylsilyl ester thermolysis.
