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

Direct trifluoromethylthiolation and trifluoromethylsulfinylation reactions by using sodium trifluoromethanesulfinate were promoted by different phosphorus reagents to selectively occur under mild and transition‐metal‐free conditions. In the presence of phosphorus trichloride, sodium trifluoromethanesulfinate readily underwent a reaction with indole and its derivatives in N,N‐dimethylformamide (DMF) at room temperature to give 3‐trifluoromethylthiolated products in good yields. Trifluoromethylsulfinylation reactions, however, occurred at the C‐3 position when phosphorus oxychloride was used to give the corresponding sulfoxides in high yields. This protocol was further extended to the use of other sodium perfluoroalkanesulfinates. A facile method for the selective trifluoromethylthiolation and trifluoromethylsulfinylation of indoles was developed. Sodium trifluoromethanesulfinate was used in the preparation of a series of trifluoromethylthio‐ and trifluoromethylsulfinyl‐containing compounds in good yields under mild and transition‐metal‐free conditions.