Enantioselective Synthesis of 3-Iodo-4-arylcoumarinyl Atropisomers via Cu-Catalyzed Asymmetric Ring-Opening of Cyclic Hetero Diaryliodoniums

Axially chiral biaryl compounds are privileged scaffolds in asymmetric catalysis, yet the catalytic asymmetric ring-opening of cyclic diaryliodonium salts remains limited to symmetric biphenyl derivatives. Herein, we report a Cu-catalyzed asymmetric ring-opening of arylcoumarinylcyclic iodonium salts, affording axially chiral 3-iodo-4-arylcoumarins with excellent enantioselectivity (up to 99% ee). The reaction proceeds with high regioselectivity, exclusively cleaving the less sterically encumbered C-I bond. Notably, distinct bisoxazoline ligands optimize different transformations: L5 for carboxylic acid-mediated oxygenation reactions and cycloheptane-containing L9 for asymmetric thiolation. This work expands asymmetric ring-opening from biaryl to aryl-heteroaryl systems, providing efficient access to axially chiral heteroaryl frameworks.