Transalkylation of alkyl aryl sulfides with alkylating agents

The reaction of methyl iodide with tert-butylphenylsulfide in DMF leads to a transalkylation that produces methylphenylsulfide. This transalkylation reaction was further studied by ¹H NMR spectroscopy. The polarity of the solvent, the electron density on the sulfur atom, and the strength of the alkylating agent (MeI, EtI, BuI, dimethyl sulfate, or dimethyl carbonate) played important roles in the reaction. The suggested mechanism of the reaction involves the formation of a dialkyl aryl sulfonium salt that subsequently eliminates the radical. This mechanism was supported by the observation of higher conversion rates for compounds with more branched alkyl groups on the sulfur atom, which may lead to the formation of more stable radicals.