Visible-light-mediated C2-amination of thiophenes by using DDQ as an organophotocatalyst

Abstract

In this work, a direct C–H activation of thiophenes was presented via an oxidation pathway under visible-light irradiation, in which the thiophene radical cation serves as the key intermediate. Various thiophenes and azoles could be transformed into the corresponding amination products well, and H₂O was the only byproduct which is environmentally benign. Our results showed that tert-butyl nitrite (TBN) served as the electron transfer mediator and O₂ as the terminal oxidant to regenerate the photocatalyst DDQ and revive the photocatalytic cycle.