Galactose oxidase model: Biomimetic enantiomer-differentiating oxidation of alcohols by a chiral copper complex

An enantiopure analogue of galactose oxidase (GO) was synthesized from an easily and readily available source with a similar activity of GO's in primary alcohol oxidation and enantioselective catalysts for aerobic oxidative kinetic resolution (AORK) of racemic secondary alcohols. Enantiopure (R)-binam was treated with Cu(OTf)2 in toluene at room temperature for one hour to give a (R)-binam-Cu complex. It is found that enantiopure benzoin is an important intermediate in the synthesis of a potent anticancer agent and can been synthesized by enzymatic hydrolysis with benzaldehyde lyase (BAL). The S enantiomer of the racemate is oxidized faster to the corresponding benzil and the slow-reacting R enentiomer of benzoin is recovered in an enantiomerically enriched form. It is also observed that ortho substitution reduces the rate of reaction, while a reduced enentioselectivity is observed in case of ortho-substituted benzoin.