Stepwise catalytic transformations of renewable feedstock arising from plant oils
Résumé
Two synthetic approaches to produce functionalized plant oil derivatives were investigated. The ruthenium-catalyzed ene-yne cross-metathesis of propargylic carbonates with terminal olefins arising from ethenolysis of methyl oleate provides conjugated dienes. It was shown that the reactivity of these dienes in Diels-Alder [4 + 2]-cycloaddition with symmetrical electron-deficient alkynes towards the formation of cyclohexadienes was effective but limited by stereochemical considerations. On the other hand, the stepwise ene-yne cross-metathesis followed by ruthenium-catalyzed nucleophilic allylic substitution by O, N, and C-nucleophiles was very efficient both in term of reactivity and regioselectivity.