Synthesis of 2-substituted 3-trifluoromethylselenoindoles via a SeCF3 migration reaction

Abstract

A novel method for the synthesis of 2-substituted 3-trifluoromethylselenoindole derivatives from readily accessible 2-trifluoromethylseleno ethynylanilines via a zinc-mediated SeCF₃ group migration is achieved. This tandem reaction starts with cyclization/nucleophilic addition, followed by an unprecedented trifluoromethylseleno group 1,2-migration and then electrophilic substitution. A zincoindole complex with C_indolyl/O_tosyl chelation is successfully isolated as the reactive intermediate and characterized by X-ray diffraction. Control experiments indicate that both the nature of the selenium atom and N-protecting groups play a crucial role in the rearrangement reaction.