We here report a manganese-based oxidative cleavage of inactivated acetylacetonate, the mechanistic pathway of which resembles Dke1-catalyzed reactions of β-diketone and α-keto acid. This oxidative transformation proceeds through an acetylacetonate-pyruvate-oxalate pathway, which can be terminated at the stage of pyruvate through ligand/solvent variation. XRD, time-dependent GC-MS, and isotope-labeling studies suggested that our system represents the same cleaving specificity and dioxygenase-like reactivity of Dke1.