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

Abstract

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(sp²)–H/O–H cross-dehydrogenative coupling of phenols and tertiary anilines to synthesize diaryl ethers. The C(sp²) 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).