CATA-LUX was a very successful project. We have addressed all the milestones and the objectives originally planned, including the more challenging ones. Despite the second part of the project developed during the COVID pandemic, the CATA-LUX team could continue the research activities in a successful way.
CATA-LUX aimed to deliver conceptually novel strategies for efficiently making chiral molecules using light. The main target was to establish the potential of key organocatalytic intermediates to participate in the photoexcitation of substrates. In this context, we have successfully developed an enamine-based EDA complex activation for the enantioselective formal α-methylation and α-benzylation of aldehydes (reported in Angew. Chem. Intl. Ed. 2017, 56, 4447), a chemical transformation for which there is no counterpart in the traditional ground-state regime. We have also identified that chiral iminium ions can directly reach an electronically excited state upon light absorption to become strong chiral oxidants that can activate reagents via single-electron transfer manifolds. The resulting visible-light-mediated strategy was used for the asymmetric C−H functionalization of toluene derivatives. This study showed that feedstock chemicals generally used as solvents, such as toluene, can be used as substrates for making chiral molecules with high enantioselectivity. The results were published in J. Am. Chem. Soc. 2018, 140, 8439. This novel strategy has brought about the development of many unconventional methodologies, published in Nature Chem. 2017, 9, 868; Angew. Chem. Int. Ed. 2018, 57, 1068; Angew. Chem. Int. Ed. 2019, 58, 1213; Angew. Chem. Int. Ed. 2021, 60, 5357, among others.
The scientific results of CATA-LUX allowed me to further consolidate my role within the field of organic synthesis, photochemistry, and enantioselective catalysis. As a recognition of these achievements, I was recently invited to write a review to outline the historical context and the scientific motivations for combining photocatalysis and organocatalysis. The manuscript has been published in a topical interdisciplinary journal: "Expanding the potential of enantioselective organocatalysis with light”, Nature 2018, 554, 41-49.
Many of the developed strategies are based on the photoactivation of molecules based on the formation of electron donor-acceptor (EDA) complexes, which was the underlying photochemical principle of CATA-LUX. Recently, I wrote a review to detail the synthetic potential of the EDA complex strategy, which was pioneered by my research group thanks to the present ERC project and has now evolved into an active research field, spawning over 300 publications. ‘Synthetic methods driven by the photoactivity of electron-donor acceptor complexes’, G. E. M. Crisenza, D. Mazzarella, P. Melchiorre, J. Am. Chem. Soc. 2020, 142, 5461–5476 (manuscript already cited about 200 times).
We expect that the knowledge and the new methodologies developed during CATA-LUX could provide fresh opportunities to design new stereocontrolled processes for making chiral molecules using visible light
