74032-60-3

Upstream product

• 392-41-6 methyl trifluoropropenoate 
• 79546-70-6 methyl 3-chlorodifluoropropenoate 
• 74032-61-4 dimethyl trans-perfluoro-(4-methyl-2-pentene)dioate 

Relevant academic research and scientific papers

Unusual β,β′-coupling and β-alkylation of methyl 2,3,3-trifluoropropenoate by lithium diorganocuprates

Methyl 2,3,3-trifluoroprop-2-enoate (1) reacts with lithium diorganocuprates in two ways, by fluorine substitution at C-3 with alkyl or aryl, or by β,β′ C,C-coupling. The reaction product was strongly dependent on the organyl structure: while dibutyl- or diphenylcuprate reacted by C-3 substitution, dimethylcuprate afforded the product of the coupling, dimethyl (Z,Z)-2,3,4,5-tetrafluorohexa-2,4-dienedioate (3). (Z)-Configuration is highly prevailing in 3-alkylated 2,3-difluoropropenoates (77-90% rel.).

ANIONIC cis-trans ISOMERIZATION OF DIALKYL PERFLUORO(4-METHYL-2-PENTENE)DIOATES. A NON-CLASSICAL EQUILIBRIUM DEPENDENCE

cis-trans-Isomerization of diethyl, diisopropyl, dibutyl and dicyclohexyl perfluoro(4-methyl-2-pentene)dioates (I-IV) was studied in solutions, containing solid potassium fluoride, in the range 20- 150 degC.The dependence of the cis-trans equilibrium on temperature for compounds I-IV is within the experimental error identical with that found for the dimethyl ester, i.e. it exihibits an extreme at 40-45 degC.This non-classical dependence cannot be described by the van't Hoff equation.The phenomenon is discussed in connection with the so-called cis-effect of fluorine substituents on a double bond.

REACTION OF CHLORODIFLUOROPROPENOATES WITH POTASSIUM FLUORIDE

Reaction of methyl 3-chlorodifluoropropenoate (I) with potassium fluoride afforded methyl trifluoropropenoate (II) which was dimerized to dimethyl perfluoro-4-methyl-2-pentenedioate (III).The reaction rate of I was not affected by the presence of the monomer II.Methyl 2-chlorodifluoropropenoate (VII) on treatment with potassium fluoride underwent dimerization and the unstable dimer X was transformed at -20 deg C into methyl 2-chloro-3,5,5-trifluoro-4-methoxycarbonyl-2,4-pentadienoate (XIII) and dimethyl 2-chloro-3-fluoro-4-trifluoromethyl-2-pentenedioate (XIV).These reactions involve a transfer of chlorine atom from the dimer X to the primarily formed 1-chloro-3,3,3-trifluoro-1-methoxycarbonylethanide (VIIa) which is transformed by this carbanion interconversion into methyl 2,2-dichlorotrifluoropropanoate (XI).The propenoate VII adds methanol in the presence of potassium fluoride whereas the propenoate I does not react under these conditions.

ANIONIC cis-trans ISOMERISATION OF DIMETHYL PERFLUORO-(4-METHYL-2-PENTENE)DIOATE

Potassium fluoride induced cis-trans isomerisation of the title compound I was investigated.The isomerisation takes place in a heterogeneous system and is enabled by solvation effect of dipolar aprotic solvents.Dimethyl 2,3,3,4-tetrafluoro-2-trifluoromethylpentanedioate (II) is formed as side product by proton transfer from the solvent to the intermediate 1,3-bis(methoxycarbonyl)-perfluoro-1-butanide (III).The mechanism was deduced from the reaction conditions and results of the isomerisation.Composition of the equilibrium mixture of cis- and trans-isomer (Ia, Ib, respectively) studied in the interval 2-75 deg C, shows an extreme.In the interval 2-30 deg C the reaction Ia to Ib appears to be exothermic (ΔH=-21.2 kJ mol-1), in the interval 35-47 deg C the enthalpy equals practically zero and in the maximum of the curve at 42.5 deg C the entropic factor ΔS=2.82 J mol-1 K-1.In the interval 50-75 deg C the reaction is endothermic (ΔH=15.2 kJ mol-1).In this context the effect of steric interaction between the substituents -COOCH3 and -CF(CF3)COOCH3, as well as of the so called cis-effect in 1,2-dihalogenoethylenes, on the Ia Ib equilibrium are discussed.

IONIC DIMERISATION OF METHYL TRIFLUOROPROPENOATE

Dimerisation of methyl trifluoropropenoate (I) in solvents in the presence of potassium fluoride affords stereoisomeric dimethyl perfluoro-(4-methyl-2-pentene)dioates (III), the ratio of which depends on the reaction conditions.The reaction is accompanied by formation of methyl 2,3,3,3-tetrafluoropropenoate (IV), arising by proton transfer from the solvent to the carbanionic intermediate.Under suitable conditions complete conversion of the propenoate can be achieved and he dimer is obtained in 80-90percent yield.Principal steps of the dimerisation were proved and the formation of configuration isomers is discussed in terms of kinetically controlled reaction.