Selective Trifluoromethylthiolation and Trifluoromethylsulfinylation of Indoles with Sodium Trifluoromethanesulfinate Promoted by Phosphorus Reagents

Direct trifluoromethylthiolation and trifluoromethylsulfinylation with sodium trifluoromethanesulfinate promoted by different phosphorus reagent were achieved selectively under transition metal-free and mild conditions. In the presence of phosphorus trichloride, sodium trifluoromethanesulfinate reacted readily with indole and its derivatives in DMF at room temperature to give 3-trifluoromethylthiolated products in good yields. While trifluoromethylsulfinylation reaction occured at C-3 position when phosphorus oxychloride was used, and the corresponding sulfoxides were obtained in high yields. The protocol could also be expanded to other sodium perfluoroalkanesulfinates.