Catalytic Oxidation–Reduction Hydration of Olefin with Molecular Oxygen in the Presence of Bis(1,3-diketonato)cobalt(II) Complexes

In the presence of a bis(1,3-diketonato)cobalt(II) complex, various olefins are converted to the corresponding hydrated products according to the Markownikov rule on treatment with molecular oxygen in secondary alcohol (“oxidation–reduction hydration”). Removal of water formed during the hydration reaction, especially by azeotropic method, is remarkably effective to improve yields of the hydrated products based on the cobalt(II) catalyst as bis(trifluoroacetylacetonato)cobalt(II) (Co(tfa)2) or bis(2-ethoxycarbonyl-3-oxobutanalato)cobalt(II) (Co(ecbo)2).