Acid-Mediated Imidazole-to-Fluorine Exchange for the Synthesis of Sulfonyl and Sulfonimidoyl Fluorides

Sulfur­(VI) fluoride motifs are important entities in organic chemistry. Typically, their syntheses involve the corresponding chlorides, which are often difficult to prepare and characterized by a poor storability due to the inherently weak S–Cl bond. Here, a single-step procedure for the preparation of sulfur­(VI) fluorides starting from sulfonyl imidazoles as stable S­(VI) reservoirs is described. By using a simple combination of AcOH and potassium bifluoride (KF2H), an imidazole-to-fluorine exchange furnishes a variety of sulfonyl, sulfonimidoyl, sulfoxyl, and sulfamoyl fluorides in good to excellent yields.