Electro-oxidative C(sp2)-H/O-H cross-dehydrogenative coupling of phenols and tertiary anilines for diaryl ether formation

The formation of diaryl ethers is generally achieved via transition metal catalyzed etherification reactions (Ullmann, Chan-Lam, Buchwald-Hartwig) with prefunctionalized aryl halide substrates at elevated temperatures. Herein, we report a protocol for electrochemical C(sp(2))-H/O-H cross-dehydrogenative coupling of phenols and tertiary anilines to synthesize diaryl ethers. The C(sp(2)) H/O-H coupling product can be obtained under metal- and oxidant-free conditions at room temperature in moderate to excellent yield (up to 83% yield) with high regioselectivity (>99% for para-substitution) and with a broad substrate scope (22 examples).

Automated summary

In this study, a high regioselective and metal- and oxidant-free method for synthesizing diaryl ethers at room temperature was reported through electrochemical C(sp(2))-H/O-H cross-dehydrogenative coupling of phenols and tertiary anilines. The coupling product was obtained in moderate to excellent yield (up to 83%) with a wide substrate scope and high regioselectivity (>99% for para-substitution).