The foundation of the study rested on combining the LUMO-lowering activation of the aluminum with the strong reducing power of the ligand chromophore in the excited state [E1/2(*PC/PC + ) ≈ -1.47 V vs. SCE]. It was reasoned that, following substrate coordination to the Al center, excitation of the ligand chromophore would induce electron-transfer to generate a transient ketyl radical: this would exist in rapid equilibrium with the achiral, ring-opened form.