Title:    Chiral Ligands Providing Attractive Noncovalent Interactions

Time:     2025-07-23 09:00

Lecturer:  Prof. Sukwon Hong

Gwangju Institute of Science and Technology

Venue:    Room 202, Lu-Jiaxi Building

Abstract：

The application of attractive noncovalent interactions has emerged as an elegant strategy in the asymmetric catalysis. Although conventional asymmetric catalysis utilizes repulsive steric interactions to destabilize transition states of minor enantiomers, attractive noncovalent interactions such as ion-pairing, hydrogen bonding, and aromatic interactions could provide an alternative ‘enzyme-like’ pathway to stabilize the transition states of major enantiomers. In our laboratory, a series of hydrogen-bond functionalized salen-transition metal catalysts were developed to facilitate bimetallic or bifunctional activation of both reaction partners. Cation‐binding salen nickel catalysts were developed for the enantioselective alkynylation of trifluoromethyl ketones in high yield (up to 99%) and high enantioselectivity (up to 97% ee). Palladium complexes with chiral pyridine-dihydroisoquinoline (PyDHIQ) ligands enabled highly enantioselective conjugate addition reactions of arylboronic acids to 2-substituted chromones and β-methyl α,β-unsaturated δ-lactams. The effect of π-interactions on the high enantioselectivity was elucidated by DFT calculations and noncovalent interaction analysis. Recently, novel chiral N-Heterocyclic Carbene (NHC)-palladium complexes featuring an anagostic C-H···Pd interaction were successfully applied to the enantioselective desymmetric C-N cross-coupling reactions.