Scheme 6. Computed mechanisms for [Co(por)]-catalysed 1,2-dihydronaphthalene formation.^a DFT-D3 calculated (Turbomole, BP86, def2-TZVP, disp3) mechanisms for [Co(por)]-catalysed 1,2-dihydronaphthalene formation (free energies, , in kcal mol^–1). All energies, including the transition states, are reported with respect to (the toluene adduct of) species A as the reference point. A cobalt–porphyrin complex without meso-substituents was used as a simplified model of the actual [Co(TPP)] catalyst.