Potassium iodide promoted thiolation of pyrazolones and benzofurans using aryl sulfonyl chlorides as sulfenylation reagents

Abstract An efficient, transition-metal-free method to synthesize pyrazolone thioethers as well as 2-aryl and 3-aryl benzofuran thioethers by employing aryl sulfonyl chlorides as sulfenylation reagents in the presence of triphenylphosphine was developed. Potassium iodide was found to facilitate the transformation for the first time by generating more reactive sulfenyl iodide in situ from sulfenyl chloride.