Aromatic ammonium and phosphonium salts are important synthetic intermediates and multifunctional materials, but para‐selective functionalization of the aromatic salts remains a challenge. Here we develop an ionic ligand based on our newly designed “biphenyl‐phenanthroline” skeleton and realize the Ir‐catalyzed para‐selective C−H borylation of seven types of aromatic quaternary ammonium and phosphonium salts. Gram‐scale transformation, late‐stage elaboration for drug molecule, and diversification of borylated products demonstrate the potential utility of this reaction. The mechanistic studies and computational analysis elucidate the origin of para‐selectivity.

Aryl sulfones and aryl sulfonamides are of great importance in organic synthesis and medicinal chemistry. Although ortho‐C−H functionalization of aryl sulfonyl compounds has been extensively explored, the functionalization of remote meta‐ and para‐C−H bonds is very rare. Herein, we report a tunable meta‐ and para‐selective C−H borylation of aryl sulfonyl compounds enabled by computationally designed ligands and iridium catalyst. This method is capable of accommodating a broad range of substrates under mild reaction conditions. Gram‐scale preparation can be achieved with iridium catalyst loading as low as 0.1 mol%. As the introduced boronate group can be easily converted into many other groups, our method provides a general solution to installing functional groups at either meta‐ or para‐position of aryl sulfones and aryl sulfonamides with good to excellent selectivity.

Aryl sulfones and aryl sulfonamides are of great importance in organic synthesis and medicinal chemistry. Although ortho‐C−H functionalization of aryl sulfonyl compounds has been extensively explored, the functionalization of remote meta‐ and para‐C−H bonds is very rare. Herein, we report a tunable meta‐ and para‐selective C−H borylation of aryl sulfonyl compounds enabled by computationally designed ligands and iridium catalyst. This method is capable of accommodating a broad range of substrates under mild reaction conditions. Gram‐scale preparation can be achieved with iridium catalyst loading as low as 0.1 mol%. As the introduced boronate group can be easily converted into many other groups, our method provides a general solution to installing functional groups at either meta‐ or para‐position of aryl sulfones and aryl sulfonamides with good to excellent selectivity.

Aromatic ammonium and phosphonium salts are important synthetic intermediates and multifunctional materials, but para-selective functionalization of the aromatic salts remains a challenge. Here we develop an ionic ligand based on our newly designed "biphenylphenanthroline" skeleton and realize the Ir-catalyzed para-selective CÀ H borylation of seven types of aromatic quaternary ammonium and phosphonium salts. Gram-scale transformation, late-stage elaboration for drug molecule, and diversification of borylated products demonstrate the potential utility of this reaction. The mechanistic studies and computational analysis elucidate the origin of para-selectivity.