Visible-light-induced aerobic C-3 thiocyanation of indoles using porphyrin as photoredox catalyst

Abstract

In this work, we report a metal-free and environmentally friendly approach for the electrophilic C-H thiocyanation of indoles under visible light irradiation. Using porphyrin as a photocatalyst and atmospheric air as an oxidant, we developed a mild and efficient route to synthesize a series of thiocyanate products with both electron-rich and electron-deficient systems in moderate to good yields. The use of a radical scavenger like TEMPO helped to establish a photoredox mechanism. This method offers a sustainable and promising approach for synthesizing heterocyclic substrates, thiocyanate aromatics, and bioactive molecules through photoredox catalysis.