Haloacrylic acids XX. Dimerisation of trifluoroacrylates. Kinetically and thermodynamically controlled reactions - Paleta, O.; Svoboda, J.; Dedek, V. (Elsevier)
The potassium fluoride-catalysed dimerisation of methyl, ethyl, isopropyl, butyl, and cyclohexyl trifluoroacrylate in various solvents in the presence of solid potassium fluoride was investigated and the main steps of the reaction mechanism were proved. The preparative yields of the dimers amounted to 74-87%. The dimerisation did not take place if potassium fluoride was dissolved in the presence of dibenzo-18-crown- -6-ether. From the high-boiling fractions two trimers of methyl trifluoroacrylate were isolated. Dimerisation kinetics in the heterogeneous system showed the reaction to be autocatalytic. The dimers are formed as a mixture of configurational isomers with the trans isomer highly prevailing under the kinetic control. The temperature dependence of the kinetic distribution of the stereoisomeric dimers was measured, and compared with the thermodynamic distribution.
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