Control of atroposelectivity via non-covalent interaction in Cu-catalyzed synthesis of axially chiral biaryls from azonaphthalenes and arylboronic acids

Abstract

DFT calculations were performed to provide mechanistic insights into the title reaction, the first example of copper-catalyzed C(sp2)−H arene arylation with high atroposelectivities for aromatic Michael acceptor reported recently by Tan et al. [J. Am. Chem. Soc. 142 (2020) 7322−7327]. The results indicate that the reaction undergoes four sequential steps: transmetalation, ligand exchange, Michael addition, central-to-axial chirality transfer. The nucleophilic addition is found as the atroposelectivity-, and regioselectivity-determining step with a barrier of 14.9 kcal/mol. The detailed mechanisms obtained lead to an in-depth understanding of the atroposelectivity, which mainly originates from the π–π stacking interaction between two naphthalene rings respectively in the BINOL-derived chiral phosphoramidite ligand and in the arylboronic acid.