An unprecedented oxygenative skeletal rearrangement reaction of tetrahydro-β-carbolines (THβCs) was developed under mild conditions enabled by copper-catalyzed single-electron transfer oxidation, in which H2O and O2 act as oxygen sources to generate a unique 2-hydroxyl-3-peroxide indoline intermediate. The process involves a multistep sequence to enable the transformation of THβCs to donaxanine-type