Electrochemical Hydroxylation of Electron‐Rich Arenes in Continuous Flow

Abstract Electrochemical hydroxylation of arenes by trifluoroacetic acid provides a straightforward access to aryl oxygen compounds under the mild and environmental benign reaction conditions. Harmful and pollutant stoichiometric amounts of oxidation reagents and the use of metal‐catalysts can be avoided. Herein, we present a novel method for the synthesis of hydroxylated products from electron‐rich arenes that was achieved by the implementation of a continuous‐flow setup. The continuous nature of the process allowed to fine‐tune the reactions conditions in order to prevent the decomposition of the sensitive products expanding the reaction scope beyond electron‐poor and neutral arenes that were previously reported in the batch processes. Thus, synthetically valuable hydroxylated arenes were obtained in good yields with the residence time just over a minute. In order to demonstrate the reliability and the efficiency of the electrochemical flow setup, a scale up experiment was also performed.