Efficient Synthesis of 3-(Arenesulfinyl)indoles in Water

The first example of the sulfinylation of indoles with arylsulfinamides in water in the presence of trifluoroacetic acid as a promoter is described. The reaction occurs smoothly at room temperature under environmentally benign conditions without any catalyst, additive, ligand, or organic solvent. The developed sulfoxide synthetic protocol is attractive due to the use of water as the solvent and provides a novel and efficient route to a wide range of functionalized diaryl sulfoxides.