Titre du professeur Cédric Theunissen : « Radical activation of carbon - halogen and carbon - nitrogen bonds using photoredox catalysis »
Titre du DR Gwilherm Evano : « Copper catalyzed cross-coupling and radical reactions »
Cédric Theunissen
Abstract: Modern synthetic chemistry has recently evolved towards the development of new procedures that are ever more straightforward, fast and environmentally friendly in order to reduce waste production and costs. This requires the design of new strategies to simplify and shorten traditional synthetic pathways for the construction of complex molecular targets from readily available starting materials in a limited number of steps. One striking example of such strategies is certainly photoredox catalysis which has profoundly changed the way we carry out radical chemistry, which has long remained underexploited despite being known for decades to promote a wide range of transformations with remarkable efficiencies. The development of photoredox catalysis has seen the emergence of numerous photoredox catalysts, mainly based on noble metal such as iridium and ruthenium, as well as of a plethora of new radical precursors. In order to address some limitations inherent to the use of noble metal complexes, our group recently reported the use of a copper-based photoredox catalyst for the radical activation of aryl and alkyl halides. Application of this system to the preparation of small nitrogen heterocycles will be discussed. In parallel to this work, we have also started to study the radical activation of carbon – nitrogen bonds in ammonium salts for the development of new deaminative processes and our latest results will also be discussed.
Biosketch: Cédric Theunissen studied chemistry at the Université libre de Bruxelles (ULB) where he received his PhD in 2016 under the supervision of Prof. Gwilherm Evano, working on new copper-catalyzed reactions. He then moved to the US for postdoctoral studies with Prof. Tomislav Rovis at Columbia University (New York) where he worked on visible-light-controlled olefin metathesis for two years. He then came back to ULB in 2018 as a FNRS postdoctoral researcher where he has since been working on the development of new processes for the radical activation of carbon – halogen and carbon – nitrogen bonds using photoredox catalysis.
Gwilherm Evano
Abstract: Organic synthesis clearly is today a central science with deep implications in various domains such as biology, medicine, or material sciences. There is thus a high and growing demand for efficient procedures to assemble or selectively functionalize complex molecules or pharmaceuticals from simple building blocks. This drive for shorter, general, and more efficient synthetic procedures, as well as the quest for molecular diversity, has fueled the development of new reactions that efficiently contributed to the selective syntheses of ever larger and more complex systems with increased efficiency. Organometallic catalysis has played a central role in this area over the last decades. Among all metal that can efficiently catalyze a range of organic reactions, copper has been extremely studied over the last twenty years, for various reasons. These include the low cost of this metal, which is one of the cheapest one that can be used in catalysis, the limited toxicity of most copper complexes, and, more importantly, the broad range of transformations that can be efficiently catalyzed with metal complexes. Indeed, the oxidation states that are readily accessible with such complexes enable not only their use in cross-coupling processes but also in oxidative cross-coupling reactions. They have also been more recently found to be remarkably efficient for the catalysis of radical processes, enabling the generation of radical species under remarkably mild conditions. Selected examples of such reactions developed in the group will be discussed.
Biosketch: Gwilherm Evano studied chemistry at the Ecole Normale Supérieure in Paris and received his PhD from the Université Pierre et Marie Curie in 2002 under the supervision of Prof. François Couty and Prof. Claude Agami. After postdoctoral studies with Prof. James S. Panek at Boston University working on natural product synthesis, he joined the CNRS as an associate professor in 2004. He then moved to the Université libre de Bruxelles, where he became the head of the Laboratory of Organic Chemistry in 2012. His research focuses on natural/bioactive product synthesis, copper catalysis, photoredox catalysis, organometallic chemistry, and on the chemistry of heteroatom-substituted alkynes and reactive intermediates. He has published more than 130 papers, 19 book chapters and has edited a book on copper catalysis. He is associate editor of Frontiers in Chemistry and has given more than 140 talks/invited lectures.
