Reactions of conjugated fatty acids. VI. Selenium catalysis, a method for preparing diels‐alder adducts from cis,trans‐octadecadienoic acid

Abstract

Summary Adducts of dienophiles and alkali‐conjugated safflower fatty acids containing conjugated linoleic acid in the cis,trans form were prepared by heating the reactants in the presence of selenium as a catalyst. The products appeared to be identical to those prepared from trans,trans conjugated linoleic acid so that isomerization of cis‐trans to trans,trans acids is eliminated as a separate step. Although yields of pure product were lower than desired because of difficulties in removing selenium, yields of crude adducts ranged from 64–82%. The adducts obtained could be epoxidized with hydrogen peroxide and an ion‐exchange resin as catalyst in 80–93% yield or with peracetic acid in 89–98% yield.