Synthesis of 2,2′-biphenols through direct C(sp2)–H hydroxylation of [1,1′-biphenyl]-2-ols

Abstract

A novel synthesis of diversely substituted 2,2′-biphenols through Pd(II)-catalyzed, ^tBuOOH-oxidized, and hydroxyl-directed C(sp²)–H hydroxylation of [1,1′-biphenyl]-2-ols has been developed. Notably, this finding is distinct from previous reports in which [1,1′-biphenyl]-2-ols underwent an intramolecular C–H activation and C–O bond formation to afford dibenzofurans under the promotion of Pd(II) but in the absence of ^tBuOOH.