Synthesis of o-Aminophenols via a Formal Insertion Reaction of Arynes into Hydroxyindolinones

A novel approach toward the synthesis of sterically hindered o-aminophenols has been achieved by a formal aryne insertion into hydroxyindolinones. This transformation offers a rapid and efficient entry to diverse o-aminophenol scaffolds under mild transition-metal-free conditions. The reaction involves the addition of hydroxyindolinones to arynes followed by a chemo- and regioselective [1,3]-rearrangement. Furthermore, the reactions of N-hydroxyindoles and arynes were found to provide the C3-aryl indole products via an alternative [3,3]-rearrangement pathway.