Redox‐Tunable Ring Expansion Enabled By A Single‐Component Electrophilic Nitrogen Atom Synthon

Controllable installation of a single nitrogen atom is central to many major goals in skeletal editing, with progress often gated by the availability of an appropriate N-atom source. Here we introduce a novel reagent, termed DNIBX, based on dibenzoazabicycloheptadiene (dbabh), which allows the electrophilic installation of dbabh to organic substrates. When indanone β-ketoesters are aminated by DNIBX, the resulting products undergo divergent ring expansions depending on the mode of activation, producing heterocycles in differing oxidation states under thermal and photochemical conditions. The mechanism of each transformation is discussed, and the different reactivity modes of the indanone-dbabh adducts are compared to other nitrogenous precursors.