Transition Metal Catalysis Towards Saturation in Organic Molecules through Alkyl Radical Chemistry

Projektinformationen

CatToSat

ID Finanzhilfevereinbarung: 101027337

DOI

10.3030/101027337

Projekt abgeschlossen

EK-Unterschriftsdatum 26 März 2021

Startdatum 1 Mai 2021

Enddatum 31 Oktober 2024

Finanziert unter

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Gesamtkosten

€ 260 840,64

EU-Beitrag

€ 260 840,64

Koordiniert durch

EIDGENOESSISCHE TECHNISCHE HOCHSCHULE ZUERICH
Switzerland

Periodic Reporting for period 2 - CatToSat (Transition Metal Catalysis Towards Saturation in Organic Molecules through Alkyl Radical Chemistry)

Berichtszeitraum: 2023-05-01 bis 2024-04-30

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

This project aims to develop useful chemical reactions using electrochemistry and alternating current as the primary driving force.

Electrochemical oxidation of ubiquitous carboxylic acids can transform them into olefins, which have wide-ranging applications in various fields, including synthetic organic chemistry and medicinal chemistry. The removal of a carboxyl group from a carboxylic acid to create an olefin is underdeveloped, and this process is a convenient tool for installing an alkene when the carboxylic acid is readily available, providing an alternative disconnection for retrosynthetic analysis.

Another area of interest is the electrochemical reduction of persistent organic pollutants (POPs) to transform them into innocuous byproducts and useful commodity chemicals. POPs are halogenated organic molecules that were produced on a megaton scale during the 20th century as crop protection agents and flame retardants. Long-term exposure to these chemicals leads to adverse health effects, including serious illnesses such as cancer and death. Unfortunately, POP-contaminated soils and waters have been abandoned and neglected worldwide, eventually leaching into the environment and causing harm when they enter the food chain. Due to their persistent nature, characterized by high stability, low chemical reactivity, and low solubility in water, POPs have been banned globally. However, there is currently no clear solution for their disposal.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

1) The mild, scalable (up to kg-scale), metal-free electrochemical activation of carboxylic acids was accomplished during the outgoing phase of this action. This transformation has numerous applications that simplify the synthesis of olefin targets derived from medicinally relevant molecules, natural products, and other feedstock chemicals. The robust method relies on alternating current to maintain the quality of electrodes used in the electrochemical cell, providing a deeper understanding of a process that exhibits unprecedented scalability (in collaboration with AbbVie) and selectivity. This methodology has been deposited on ChemRxiv (open access, https://chemrxiv.org/engage/chemrxiv/article-details/646e91bd4f8b1884b7396688) published on Angewandte Chemie, International Edition (open access, 10.1002/anie.202309157) and highlighted by Chemistry World (https://www.chemistryworld.com/news/electrochemical-conversion-of-acids-to-alkenes-achieved-on-kilogram-scale/4018090.article). These results were also presented at the 2024 Gordon Research Conference on Heterocyclic Compounds held at Salve Regina University in Newport, Rhode Island, USA.

2) The electrochemical recycling of persistent organic pollutants was accomplished during the incoming phase of this action. This electrochemical method provides an efficient, safe, and scalable platform to completely dehalogenate ubiquitous organochlorine pollutants, such as Lindane (hexachlorocyclohexanes). These compounds are transformed into harmless inorganic salts while simultaneously producing valuable commodity chemicals. This technology can effectively treat pure pollutant samples as well as low-concentration mixtures that may contain contaminated soil, filtrate, absorbers, or plastic waste. This remarkable capability underscores its potential to significantly contribute to soil and water remediation efforts. The process once again relies on alternating current to maintain the quality of electrodes used in an electrochemical cell, offering a new perspective on the impact of alternating polarity on electrochemical transformations. The implementation of this technique has the potential to have a substantial environmental impact. This methodology has resulted in a patent that is currently undergoing review, and will also produce a manuscript that will be deposited on ChemRxiv and published open access once completed.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

The work undertaken during this action is supported by groundbreaking innovation at the intersection of organic chemistry, electrochemistry, medicinal and process chemistry, and environmental science. The project aims to accomplish landmark achievements in the context of organic chemistry processes, resulting in the following:

• Unprecedented selectivity in the decarboxylation of carboxylic acids towards the synthesis of olefin products. These products offer numerous opportunities for further functionalization, lead to novel structures that cannot be accessed through other methods in the literature, or simplify the synthesis of existing products by shortening synthetic sequences, reducing synthetic costs, or providing scalable routes.

• Feasibility towards the recycling of persistent organic pollutants. This invention is based on the following features:
i) operational simplicity, which implies an inexpensive and scalable experimental setup consisting of an undivided vessel equipped with electricity, graphite as an electrode material, an organochlorine sample, and a solvent.
ii) the recycling of halide waste as innocuous salts (NaCl), achieved by introducing a sacrificial reductant that also serves as a solvent, preventing undesirable halide oxidation even in an undivided setup. iii) alternating current, employed to electrolyze the solution, dissipating local pockets of acidity and basicity throughout the vessel, thereby suppressing undesirable reaction pathways and electrode decomposition.
The method demonstrates optimal performance even in the presence of air and/or moisture, resulting in complete conversion of organochlorine pollutants regardless of concentration, location, and scale. This invention is ready for immediate worldwide application to assist in the remediation of contaminated soil and water.

General overview of the scientific research developed in the project