Synthesis of Sulfonyl, Sulfonimidoyl, and Sulfoxyl Fluorides under Solvent-Free Mechanochemical Conditions in a Mixer Mill by Imidazole-to-Fluorine Exchange

A sustainable, mechanochemical procedure for the synthesis of sulfur(VI) fluorides starting from readily available sulfur(VI) 2-methylimidazoles as stable S(VI) precursors has been developed. The transformation proceeds with potassium bifluoride (KHF2) as the fluorine source in the presence of acetic acid (AcOH) in a mixer mill under solvent-free conditions. The corresponding sulfonyl, sulfonimidoyl, and sulfoxyl fluorides are formed in good to excellent yields. Compared with the solution-based counterpart, the reaction times are shorter. This environmentally benign mechanochemical approach exhibits significant ecological advantages and requires less resources for the optimized purification by simple silica plug filtration. X = O, NTs or NBoc R = aryl, alkyl or LA' KH 2 AcOH ball milling center dot stable S(VI) reservoir center dot solvent-free center dot single step & safe center dot simple purification O, ,X RF 26 examples up to 93% yield

Automated summary

A sustainable method for synthesizing sulfur(VI) fluorides using easily available sulfur(VI) 2-methylimidazoles as stable precursors has been developed. The reaction, conducted in a mixer mill under solvent-free conditions with KHF2 as the fluorine source and AcOH as the catalyst, produces sulfonyl, sulfonimidoyl, and sulfoxyl fluorides in good yields. The mechanochemical approach offers shorter reaction times and eco-friendly advantages with simplified purification using silica plug filtration.