Facile and Selective Cross-Coupling of Phenols Using Selenium Dioxide

Nonsymmetric biphenols are important structural motifs in organic chemistry. Therefore, an easy and versatile protocol for oxidative cross-coupling is essential to generate these so-called “privileged ligands”. We developed an efficient and selective oxidative pathway to synthesize 2,2′-biphenols as well as 2,4′- and 4,4′-biphenols. The use of selenium dioxide, a stable, powerful, and commercially available oxidizer, in 1,1,1,3,3,3-hexafluoroisopropanol allowed the oxidative coupling of alkyl-, alkoxy-, and halogen-substituted phenols.