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.