Solid acid-catalyzed one-step synthesis of oleacein from oleuropein

In this study, we developed a new synthetic strategy to convert secoiridoid glucosides into unique dialdehydic compounds using solid acid catalysts. Specifically, we succeeded in the direct synthesis of oleacein, a rare component of extra-virgin olive oil, from oleuropein, which is abundant in olive leaves. Whereas the conventional total synthesis of oleacein from lyxose requires more than 10 steps, these solid acid catalysts enabled the one-step synthesis of oleacein from oleuropein. A key step in this synthesis was the selective hydrolysis of methyl ester. Density functional theory calculations at the B3LYP/631+G (d) level of theory revealed the formation of a tetrahedral intermediate bonded to one H2O molecule. These solid acid catalysts were easily recovered and reused at least five times by simple cleaning. Importantly, this synthetic procedure was not only applicable to other secoiridoid glucosides, but could also be employed for the corresponding scale-up reaction using oleuropein extracted from olive leaves as the starting material.

Automated summary

This study developed a new synthetic strategy using solid acid catalysts to convert secoiridoid glucosides into unique dialdehydic compounds. The researchers successfully synthesized oleacein, a rare component of extra-virgin olive oil, from oleuropein in one step. The solid acid catalysts enabled the selective hydrolysis of methyl ester, leading to the formation of a tetrahedral intermediate. The synthetic procedure was not only applicable to other secoiridoid glucosides, but also suitable for scale-up reactions using oleuropein extracted from olive leaves as the starting material.