"Harnessing configurational stability: an opportunity for the design of chiral metal-based complexes and the development of new reactions

In enantioselective transition-metal catalysis, chiral ligands are key players. The
success of N-heterocyclic carbenes (NHCs) as stable electron-rich neutral ligands in
homogeneous catalysis led to the development of a wide array of chiral NHCs as
stereodirecting ancillary ligands for various asymmetric reactions.1
Recently, we devised a new design of chiral NHC-metal complexes based on restricted
rotations of dissymmetric aryl groups as N-substituents of the NHC ligands.2
Advantageously, this design does not require the use of chiral synthons since the axis
of chirality is created during the metalation step. However, NHC-metal complexes are
formed as racemic. Thanks to the high chemical stability of most of NHC-metal
complexes, a resolution by chiral HPLC at preparative scale enabled to obtain both
enantiomers with high yields and excellent enantioselectivities.

Details concerning the syntheses, configurational stabilities and the values of the
rotational barriers will be presented.3,4 Series of chiral palladium-, copper-, gold- and
ruthenium-NHC complexes have been prepared and their application in
enantioselective catalysis allowed to reach high level of enantioselectivities.2-7

References
1. D. Janssen-Müller, C. Schlepphorst, F. Glorius, Chem. Soc. Rev. 2017, 46, 4845-4854. DOI : 10.1039/C7CS00200A
2. L. Kong, J. Morvan, D. Pichon, M. Jean, M. Albalat, T. Vives, S. Colombel-Rouen, M. Giorgi, V. Dorcet, T. Roisnel, C.
Crévisy, D. Nuel, P. Nava, S. Humbel, N. Vanthuyne, M. Mauduit, H. Clavier, J. Am. Chem. Soc. 2020, 142, 93-98.
DOI: 10.1021/jacs.9b12698
3. L. Kong, Y. Chou, M. Jean, M. Albalat, N. Vanthuyne, P. Nava, S. Humbel, H. Clavier, Adv. Synth. Catal. 2021, 363,
4229-4238. DOI : 10.1002/adsc.202100491
4. M. Savchuk, L. Bocquin, M. Albalat, M. Jean, N. Vanthuyne, P. Nava, S. Humbel, D. Hérault, H. Clavier, Chirality
2022, 33, 13-26. DOI : 10.1002/chir.23378
5. L. Kong, Y. Chou, M. Albalat, M. Jean, N. Vanthuyne, P. Nava, S. Humbel, H. Clavier, Dalton Trans. 2023, 52, 8728-
8736. DOI : 10.1039/D3DT01182H
6. J. Morvan, D. Bouëtard, L. Kong, Y. Chou, T. Vives, M. Albalat, T. Roisnel, C. Crévisy, P. Nava, S. Humbel, N.
Vanthuyne, H. Clavier, M. Mauduit, Chem. Eur. J. 2023, e202300341. DOI : 10.1002/chem.202300341
7. Y. Chou, M. Vançon, M. Albalat, C. Deschodt, P. Nava, S. Humbel, N. Vanthuyne, H. Clavier, Eur. J. Inorg. Chem.
2024, e202300780. DOI : 10.1002/ejic.202300780