Synthesis of β-Truxinate via [2+2] Cycloaddition of Methyl 4-Nitrocinnamate: Kinetic Study of its Isomerization with DBU.

This work concerns the isomerization of the product obtained by dimerization of methyl 4-nitrocinnamate. Subsequent isomerization was performed using 1,8 diazabicyclo [5.4.0] undec-7-ene (DBU) as a base to obtain the corresponding ζ- and δ-truxinate derivatives. The process was monitored by 1HNMR spectroscopy in different deuterated solvents with a wide range of dielectric constants, acetonitrile-d3, acetone-d6, tetrahydrofuran-d8, and benzene-d6. Each solvent was found to have a distinct influence on the reaction’s rate constant k, with acetone-d6 yielding the highest ratio of ζ-truxinate derivative. Kinetic analysis of the reaction provided valuable information about the mechanism involved in the isomerization process.