Site-Selective Electrophilic Trifluoromethylthiolation for the Synthesis of C5- or C7-SCF₃-Substituted Indolines

We report herein an efficient and site-selective electrophilic trifluoromethylthiolation of indolines. In the absence of any catalyst or additive, C5-selective trifluoromethylthiolation could proceed at room temperature. With palladium used as the catalyst, the selectivity was reversed completely, giving C7-selecive trifluoromethylthiolated products. This reaction features good functional group tolerance, simple operation, mild conditions, and scale-up application. The potential utilities of the products were shown by further transformations.