Sustainable Sulfonylation and Sulfenylation of Indoles with Thiols through Hexamolybdate/H₂O₂-Mediated Oxidative Dehydrogenation Coupling

Arylsulfonylindole and arylsulfenylindole motifs stand as privileged scaffolds in drug discovery. Traditional methods for synthesizing these molecules have relied mainly on prefunctionalized precursors, involving multistep processes and generating a large amount of waste. In this study, we present a modular protocol for the preparation of 3-sulfonylindoles and 3-sulfenylindoles using indoles and thiols as starting materials via hexamolybdate/H₂O₂-mediated oxidative dehydrogenative C-S coupling. Notably, this method features a simple reaction setup and uses readily available thiols as a sulfide source, H₂O₂ as a green oxidant and oxygen source, alcohol as solvent, recyclable hexamolybdate as a catalyst, and water as the sole byproduct. These metrics are an acceptable green organic synthesis process.