N-directed, Co-catalyzed functionalization of distal C(sp3)–H bonds with phenols: arylation vs. aryloxylation

Abstract

Chemo- and regioselective functionalization of free phenols is a continuing challenge. Herein, cobalt-catalyzed cross-dehydrogenative coupling (CDC) of phenols with distal C(sp³)–H bonds is achieved. The reaction exhibits good to excellent chemo- and regioselectivity, delivering ortho-alkylated phenols and alkyl aryl ethers, respectively. The reaction could involve a radical process, and the presence of Na₂CO₃ or DBU in combination with the Co catalyst is essential for the chemo- and regioselectivity.