Synthesis Of (E)-1-Aryl-4,4,4-Trifluoro-1-Butene

The introduction of fluorine atoms in molecules has a great influence on their physical,biological properties and chemical reactivity.Compared with hydrocarbons,fluorine-containing compounds tend to show high thermal and oxidative stability,low polarity,weak intermolecular interactions,and small surface tension.Therefore,the synthesis and properties of fluorine-containing compounds have been favored for many years.Among numerous fluorine-containing compounds,trifluoromethyl group constitutes an important structural motif of many biologically active compounds.In the previous study of the ester-ketone exchange reaction,our research group synthesized a series of(Z)-trifluoromethyl alkenyl triflates with various functional groups in a simple and efficient manner using the "two-step one-pot method",and successfully used this bulding block in the synthesis of various fluorine-containing compounds.In this paper,based on the previous research of the research group,(Z)-trifluoromethyl alkenyl triflate is further studied on its derivatization:Firstly trifluoromethanesulfonic anhydride was used to capture the trifluoromethylenol anion generated in the ethyl trifluoroacetate/aryl ketone exchange reaction,and the substrates(Z)-trifluoromethyl alkenyl triflate were synthesized.Then,the reaction of(Z)-trifluoromethyl alkenyl triflate and p-toluenesulfonyl hydrazide under the action of the base was synthesized,and a series of(E)-1-aryl-4,4,4-trifluoro-1-butene compounds were synthesized.The effects of different bases,reaction temperature,reaction time,reaction solvents and other factors on the yield were investigated,and the reaction conditions were optimized.The reaction of different substrates shows that the substrates with alkyl,alkoxy,halogen,trifluoromethyl,etc.on the aromatic ring can react,and the substrates containing electron-donating groups have good applicability and separation.The yield is 45% to 81%;the yield of substrates containing electron-withdrawing substituents is low(29% to 35%);when the 1-position is alkyl,it does not react.