5,8-Di-tert-butyl-2-hydroxy-1H-benzo[de]isoquinoline-1,3(2H)-dione—A New Lipophilic N-oxyl Radical Precursor

N-hydroxyimides are widely known as organocatalysts for aerobic oxidation and oxidative coupling reactions, in which corresponding imide-N-oxyl radicals play the role of catalytically active hydrogen atom abstracting species. The drawbacks many poor solubility low polarity solvents limited activity cleavage unactivated C–H bonds. To overcome these shortcomings, we have synthesized a new lipophilic N-hydroxyimide, 5,8-di-tert-butyl-2-hydroxy-1H-benzo[de]isoquinoline-1,3(2H)-dione, with high low-polarity such DCM. According to EPR study, stability radical is comparable that non-tert-butylated analogue, naphthalimide-N-oxyl radical. DFT calculations showed NO–H bond dissociation enthalpy (BDE) tert-butylated-N-hydroxynaphthalimide one highest N-hydroxyimide series, corresponds reactivity may be useful catalysis strong cleavage. compound can considered catalyst liquid-phase free-radical reactions non-polar media where was previously limiting factor.