Abstract
‘Bare’ FeO^+^ reacts in the gas phase with norbornane with collision efficiency, and the most prominent cationic products correspond to [FeC~5~H~6~]^+^ (32%), [FeC~7~H~8~]^+^ (19%), [FeC~3~H~6~O]^+^ (19%) and [FeC~6~H~6~]^+^ (14%), which are structurally characterized by ligand exchange as well as collision‐induced dissociation experiments. Circumstantial evidence is provided which indicates that the complexes [FeC~5~H~6~]^+^, [FeC~7~H~8~]^+^, and [FeC~6~H~6~]^+^ originate from an Fe(norbornene)^+^ intermediate which itself is formed by elimination of H~2~O from the [FeO(norbornane)]^+^ encounter complex. Although the reactions are preceded and/or accompanied by partial H/D exchange, the isotope distribution in the productions clearly points to a preferential endo‐attack of bare FeO^+^, with an endo/exo‐ratio of ca. 10.3 and kinetic isotope effects k~H~/k~D~ for the endo‐abstraction of 2.4 and of 7.7 for approaching an exo‐CH bond. The preferred endo‐approach of bicyclo[2.2.1]heptane by ‘bare’ FeO^+^ is in distinct contrast to the P‐450‐mediated or the iron(III)porphyrin‐catalyzed hydroxylation of this substrate which favor reactions at the exo‐face.