Noboru Kobayashi

Hydroacylation of Azodicarboxylates with Aldehydes Using CoO–Fe3O4

Significance: Magnetite-supported cobalt oxide (CoO–Fe3O4) was prepared by mixing CoCl2·6H2O and Fe3O4 in water followed by treatment with NaOH (eq. 1). CoO–Fe3O4 catalyzed the hydroacylation of azodicarboxylates 1 with aldehydes 2 in trichloroethylene to afford the hydroacylated products 3 in up to 99% yield (eq. 2). Comment: In the formation of 3a, the catalyst was recovered by magnetic separation and reused nine times with slight loss of its catalytic activity. The catalytic activity of CoO–Fe3O4 was superior to that of the other metal oxides supported on Fe3O4 (NiO–Fe3O4, CuO–Fe3O4, Ru2O3–Fe3O4, Rh2O3–Fe3O4, PdO–Fe3O4, Ag2O/Ag–Fe3O4, WOx–Fe3O4, OsO–Fe3O4, PtO/PtO2–Fe3O4, Au2O3/Au–Fe3O4, NiO/Cu–Fe3O4, PdO/Cu– Fe3O4) and unsupported CoO. CoCl2⋅6H2O Fe3O4 H2O NaOH