From sunflower oil toward 1,19-diester: Mechanistic elucidation

► Combined transesterification and isomerizing methoxycarbonylation of sunflower oil. ► We elucidate the reaction mechanism obtained from experiments and DFT. ► Preformation phase of the catalyst is part of the reaction and proceeds via a PdI. ► We find the rate-determining step to proceed via intramolecular attack of MeOH. ► We find this mechanism may generally be applicable to all plant oils.