Mechanistic Studies on the O2-mediated Oxidation of Olefins in the Presence of (Schiff-base)Mn(III) Catalyst and NaBH4

Molecular oxygen would be the most desirable oxidant in organic synthesis due to its economically and environmentally favorable properties.A lot of efforts has long been made to utilize the oxygen molecule as the oxidizing reagent under mild reaction conditions.Probably, the most successful strategies have been the employment of the transition metals as the catalyst for the activation of oxygen molecule.Recently, we have reported the oxidation of olefins to the corresponding alcohols using oxygen molecule as the oxidant, where (schiff-base)Mn(III) complexes were used as the catalysts in the presence of sodium borohydride (eq.1). 1 During the study of this reaction, we were tempted to investigate reaction mechanism.Described here are the results of our experimental observations and subsequent mechanistic conclusions.