Abstract
Preservation of the biodiversity is a major issue. Its loss disrupts biological balances which are essential for human quality of life. The proliferation of invasive alien species (IAS) is one of the five key direct drivers that are responsible for biodiversity loss. IAS are species that were introduced by human beings outside of their natural range. They multiply at an uncontrollable rate and constitutes a threat to indigenous species. At the scale of our planet, the global cost of their proliferation is estimated at 423 billion USD. Since 2018, the Laboratory of Bio-Inspired Chemistry and Ecological Innovations (ChimEco) have been studying natural techniques to control the proliferation of IAS which invade aquatic ecosystems and wetlands. In accordance with the biodiversity national strategy, the laboratory completes these projects by working on the original valorization of the IAS, which aims to support the viability of the proliferation control projects. The specific physiology of IAS and their vegetative dynamics are linked to an unusual mineral composition, which is the starting point of a new generation of natural catalysts forming a new class of interesting biomaterials for the sustainable organic synthesis. This thesis is centered on the study of the synthetic potential of this new generation of ecocatalysts®. The first part introduces the environmental context in which this work takes place. Next, the synthesis results are displayed. Two different reaction mechanisms were studied: oxidations (part 2) and basic catalysis (part 3). The identification of IAS that are able of rhizofiltrating manganese in their natural habitat lead to the production of oxidative ecocatalysts® with original structures which is presented in the second part of this manuscript. Their specific reactivity was used in the total synthesis of cuminaldehyde following a biomimetic strategy. Beyond cuminaldehyde, this approach allowed to access different high-valued cyclic oxyterpenes such as β-pinene oxide, an interesting platform molecule, or perillaldehyde, which exhibits multiple biological applications. The richness of IAS growing in wetlands lead to basic ecocatalysts® with unique structures presented in the third part. Their reactivity was studied through the transesterification of fatty esters to prepare totally biosourced glyceryl fatty esters. To explore and optimize these reactions, statistical tools, such as correlations matrix and designs of experiments were used. This study got industry groups interested and allowed to answer multiple demands in feasibility, purity and naturality. This work takes part in the development of ecocatalysis by developing various examples of complete and possibly industrializable synthesis in sustainable chemistry. This new scientific approach is an answer to the key environmental issue that is the proliferation of IAS.