Solvent-switchable regioselective 1,2-or 1,6-addition of quinones with boronic acids

An efficient copper-catalyzed solvent-switchable regioselective 1,2- or 1,6-addition of quinones with boronic acids has been developed. This novel catalytic protocol for the synthesis of various quinols and 4-phenoxyphenols was enabled by a simple solvent swap between H2O and MeOH. It features mild reaction conditions, simple and easy operation, broad substrate scope and excellent regioselectivity. The gram-scale reactions as well as the further transformations of both addition products were also successfully investigated.