Aerobic epoxidation of alkenes using polymer-bound Mukaiyama catalysts

Nickel(II) acetylacetonate bound to polybenzimidazole has been shown to be an efficient catalyst for the aerobic epoxidation of alkenes with an aldehy de as co-reactant. Rates of reaction and yields of epoxide are higher with this system than with dissolved Ni(II) acetylacetonate under otherwise iden tical conditions. The polymer-bound complex acts as a heterogeneous catalys t and can be recovered from the reaction mixture. Some loss of activity is observed upon re-use of the catalyst due to leaching of the metal complexes .