Visible-Light-Induced Metal-Free Selenation of Tryptamines/3-Substituted Indoles

Visible-light-mediated novel metal-free, oxidant-free phosphoric acid-catalyzed method for the synthesis of 2-selanyl NHCbz-tryptamines/3-subtituted indoles is presented. This direct C-2 selenation strategy, with environmental benign conditions by reaction of tryptamines/3-substituted indoles and diaryl/dialkyl selenides, allows access to a wide range of 2-aryl/alkylselanyl NHCbz-tryptamines/3-substituted indoles. An experimental investigation using UV/Vis, cyclic voltammetry, and controlled experiments sheds light on the plausible mechanism.