Dioxygenation of unprotected mesoionic N-heterocyclic olefins

Abstract

We report the dioxygenation of mesoionic N-heterocyclic olefins (mNHOs) using molecular dioxygen. For 1,2,3-triazole-derived mNHOs possessing a vinyl proton and at least one acidic C–H group, they are oxidized into the corresponding triazolium benzoate salts, whereas those without vinyl proton or an acidic C–H group are oxidized into triazolium oxide and ketones/aldehydes.