Effective Trap of Zwitterionic Intermediate during Oxygenation of Electron-Rich Naphthalenes with Singlet Oxygen by the Intramolecular Alcohol

The presence of a zwitterionic intermediate during the oxygenation of electron-rich naphthalenes with singlet oxygen is clarified by the clean and efficient formation of hydroperoxide via nucleophilic addition of the intramolecular alcohol to the intermediate and by its stereochemical analysis using an optically active linker of the alcohol.