Acetonitrile–Hexane Extraction Route to Pure Sulfonium Salts

A rapid,
simple procedure is described for synthesizing trialkyl,
dialkylaryl, and alkyldiaryl sulfonium salts that features a selective
extraction procedure to access analytically pure sulfonium salts.
Alkylation of dialkylsulfides, alkylarylsulfides, and diarylsulfides
followed by partitioning between acetonitrile and hexanes efficiently
separates nonpolar reactants and byproducts, the usual impurities,
to afford analytically pure crystalline and noncrystalline sulfonium
salts. The method is efficient, general, and particularly well suited
for the preparation of oily sulfonium salts that are otherwise extremely
difficult to purify.