Abstract
Rate constant of Diels-Alder addition reaction of maleic anhydride or dimethyl maleate to methyl trans-9, trans-11-octadecadienoate was determined. From the results of rate measurement, the dienophilic activity of maleic anhydride was observed to be about one thousand times as great as that of methyl acrylate. On the other hand, the dienophilic activity of dimethyl maleate was only about one-third of methyl acrylate. The maleic anhydride adduct (mp 72.473.2°C) recrystallized from n-heptane was confirmed to be the endo configuration by NMR analysis.
The addition reaction of dimethyl maleate to the octadecadienoate gave cyclic adducts, and NMR, IR, and MS spectral analyses of the adducts showed that they were a mixture of the endo adduct of dimethyl maleate which had the same configuration as that of methyl ester derived from the maleic anhydride adduct and, presumably, the adduct of dimethyl fumarate, which would be formed by thermal isomerization of dimethyl maleate during the addition reaction.
