Electrochemical C−H Functionalization of (Hetero)Arenes—Optimized by DoE

Abstract

A novel approach towards the activation of different arenes and purines including caffeine and theophylline is presented. The simple, safe and scalable electrochemical synthesis of 1,1,1,3,3,3‐hexafluoroisopropanol (HFIP) aryl ethers was conducted using an easy electrolysis setup with boron‐doped diamond (BDD) electrodes. Good yields up to 59 % were achieved. Triethylamine was used as a base as it forms a highly conductive media with HFIP, making additional supporting electrolytes superfluous. The synthesis was optimized using Design of Experiment (DoE) techniques giving a detailed insight to the significance of the reaction parameters. The mechanism was investigated by cyclic voltammetry (CV). Subsequent transition metal‐catalyzed as well as metal‐free functionalization led to interesting motifs in excellent yields up to 94 %.

Abstract

An alternative route for the activation of different arenes including caffeine and theophylline, optimized by design of experiment techniques is presented. We provide a simple electroorganic protocol using BDD electrodes in undivided cells for the synthesis of aryl 1,1,1,3,3,3‐hexafluoroisopropyl ethers. The value of these fluorinated ethers for subsequent functionalization with a variety of nucleophiles has been proved (see scheme).