To complement the experimental data, the mechanism of racemization was further investigated with DFT calculations (Fig. ). A conformational analysis of the complex (R/S)-CP1 formed from cyclopropyl ketone (R/S)-1 and catalyst (R,R)-Al-1 revealed non-covalent London dispersion interactions between the aryl rings of the ligand and substrate, but no O-Al bond in the preferred structures. Furthermore, no significant energetic discrimination of the two enantiomers of 1 at this complexation stage was noted. With TD-DFT, very similar vertical excitation energies to the first and second singlet states (S1, S2) of (R/S)-CP1 were found. Both excited states were characterized by significant charge transfer from occupied ligand orbitals of the catalyst to the lowest virtual orbitals of the benzoyl moiety in the ketone. Based on the assumption that the conformational process required for deracemization occurs in the long-lived triplet state, the charge separated triplet diradicals (R/S)-3 INT1 were considered as initial intermediates after intersystem crossing.