Development of Structurally Defined Axially Chiral Biaryls Through Chalcogen-Bonding Interaction and Their Application to Dirhodium(II) Paddlewheel Complex

Chalcogen-bonding interaction has been recognized as a non-covalent interaction that plays a role in determining the conformation of pharmaceuticals and organic materials. This account describes a strategy to establish conformational control of axially chiral biaryls through chalcogen-bonding interaction and their application to dirhodium(II) paddlewheel complex. We prepared binaphtho- and bibenzocarcogenophene dicarboxylic acids bearing sulfur and selenium atoms in their fused aromatic rings as novel types of axially chiral functionalized dicarboxylic acid. The carboxy groups of these dicarboxylic acids were found to be conformationally locked in co-planar geometry toward the fused ring systems through chalcogen-bonding interaction (S…O or Se…O interaction). Contribution of the chalcogen-bonding interactions was proved by X-ray as well as NBO analyses in DFT calculation. Furthermore, N- and O-protected axially chiral binaphthothiophene δ-amino acids were synthesized and applied for derivatization to the artificial dipeptide. The crystal structure of the dipeptide also revealed that the carbonyl groups of both the amide and the ester moieties were conformationally fixed with naphthothiophene rings in co-planar geometry via chalcogen-bonding interaction. Finally, we employed the chalcogen-bonding interactions to lock the conformation of the dirhodium(II) carboxylate complex. This conformationally defined complex worked as an outstanding catalyst for highly stereoselective intramolecular C-H insertion reactions to α,β-diaryl γ-lactones. These results exemplified that the utility of chalcogen-bonding interaction for controlling the stereostructure of catalyst.