The ORGANO-GOLD CAT project started with the study of the possibility to merge non covalent organocatalysis (base catalysis and phase transfer catalysis) with gold-catalyzed cycoisomerisation of 2-alkynyl-enones.
Among the different transformations proposed in the project, none could be succesfully implemented due to inherent problems of reactivity, and apparent incompatibility of the
two catalytic systems. In ths context, it has been envisionned to modify the catalytic system, by changing from gold to other metals able to play a similar role, such as silver, platinum, copper or palladium.
However, only traces of the desired complex molecules could be isolated with low enantiomeric excess when other metals were used, showing the challenging nature of the project.
A second approach has then been studied, relying on the use of covalent organocatalysis (primary and secondary amine catalysis) instead of its non-covalent version.
Disapointingly, this new approach did not prove more successful, and in this case, none of the targeted transformations could be achieved. Deeper studies highlighted the
lack of reactivity of aminocatalitically generated enamines and poly-enamines with 2-alkynyl-enones in the presence of either gold or other metal complexes.
The targeted library of complex chiral furan-based molecules could not be prepared, meaning that it could not be exploited in collaboration with the industrial partner.
During this period, in order to secure some publications, the study of a new concept in organocatalysis has been decided in agreement with all the partners, based on the use of visible light to activate organocatalytically generated
chiral iminium ions, allowing for the enantioselective catalytic beta-alkylation of enals, a very challenging transformation never achieved through classical polar chemistry.
This study constitutes a proof of concept that iminium ions could be synthetically used in their excited state, and opens new opportunities for developping unprecedented transformations.
The high quality of the research developped allowed its publication in one of the very best journal dedicated to chemical research (Nature Chemistry, 2017, DOI: 10.1038/nchem.2748).
Furthermore, this article was highlighted in Chemistry World (
https://www.chemistryworld.com/news/new-organic-catalysts-mimic-vertebrate-vision/3007066.article(s’ouvre dans une nouvelle fenêtre)) and Chem (Chem, 2017, 2, 616-618), providing an additional worlwide visibility to the research carried out thanks to the horizon 2020 program. Finally, thanks to the MSCA funding, the results obtained have been disseminated through communications in several national and international symposium, as two posters and three oral communications: ESOC 2015 in Lisbon, XXVI reunión Bienal de Quimica Organica 2016 in Huelva, JCO 2016 in Paris, ISGC 2017 in La Rochelle.
