-Hyper-positive nonlinear effects in asymmetric catalysis: elucidating principals and applications. – Hyp-NLE

Nonlinear effects in asymmetric catalysis are a fascinating and important phenomenon, especially for rationalizing the occurrence of homochirality in life. Nonlinear effects are also an important tool for understanding the mechanism of an asymmetric reaction. In this framework, we have recently discovered chiral systems where the enantiomeric excess of the product takes much larger values for the partially resolved ligand than for the enantiopure ligand, a phenomenon that had been theorized but never observed.

In this project, we plan a systematic approach to advance this field and evaluate its impact on enantioselective catalysis in general. The objectives are to identify and understand unusual cases of nonlinear effects, in particular enantiodivergent or hyperpositive nonlinear effects. The work will also aim at elucidating the different parameters governing these catalytic reactions, at extending the models to determine the influence of reactants and products and at studying aggregation phenomena in general.

Thus, the project is divided into two interconnected objectives that will aim to:
- chemically understand how these scenarios are possible. Possible tools to decipher the reaction scheme include in situ spectroscopic investigations (such as NMR analyses), kinetic analyses, enantioselectivity studies, etc. (Task 1) and also DFT studies in collaboration with partner 2 (Task 2),
- improve and extend the first examples we have recently reported. Closely related to the first approach, we will synthetically modify ligands and evaluate new molecular structures to generate suitable catalysts for unprecedented nonlinear effects. We can then consider extending our studies to asymmetric reactions that are prone to non-routine nonlinear effects (Task 3).

In addition, our work program is supported by preliminary experimental results validating our scientific hypotheses. Through the combination of the three tasks, we will significantly contribute to a better understanding of the mechanisms of asymmetric catalysis -and of homogeneous catalysis in general- thus providing new nonlinear models that will be tools to decipher the mechanisms. This will ultimately lead to improved enantioselectivities of the studied reactions and to a different approach to enantioselective catalysis.