Experimental data suggest that there are various competing pathways for the catalytic and stoichiometric oxygenation of cyclohexane, assisted by iron-bispidine complexes and using various oxidants (H2O2, O-2, PhIO). Density functional theory calculations indicate that both Fe-IV=O and Fe-V=O species are accessible and efficiently transfer their oxygen atoms to cyclohexane. The reactivities of the two isomers each and the two possible spin states for the Fe-IV=O and Fe-V=O species are sufficiently different to allow an interpretation of the experimental data.