A Class of Amide Ligands Enable Cu-Catalyzed Coupling of (Hetero)aryl Halides with Sulfinic Acid Salts under Mild Conditions

The amide derived from 4-hydroxy-l-proline and 2,6-dimethylaniline is a powerful ligand for Cu-catalyzed coupling of (hetero)­aryl halides with sulfinic acid salts, allowing the formation of a wide range of (hetero)­aryl sulfones from the corresponding (hetero)­aryl halides at considerably low catalytic loadings. The coupling of (hetero)­aryl iodides and sodium methanesulfinate proceeds at room temperature with only 0.5 mol % CuI and ligand, representing the first example for Cu-catalyzed arylation at both low catalytic loading and room temperature.