Site‐Selective Late‐Stage Aromatic [18F]Fluorination via Aryl Sulfonium Salts

Abstract Site‐selective functionalization of C−H bonds in small complex molecules is a long‐standing challenge in organic chemistry. Herein, we report a broadly applicable and site‐selective aromatic C−H dibenzothiophenylation reaction. The conceptual advantage of this transformation is further demonstrated through the two‐step C−H [ 18 F]fluorination of a series of marketed small‐molecule drugs.