Laccase/TEMPO-mediated system for the thermodynamically disfavored oxidation of 2,2-dihalo-1-phenylethanol derivatives

An efficient methodology to oxidize β,β-dihalogenated secondary alcohols employing oxygen was achieved in a biphasic medium using the laccase from Trametes versicolor/TEMPO pair, providing the corresponding ketones in a clean fashion under very mild conditions. Moreover, a chemoenzymatic protocol has been applied successfully to deracemize 2,2-dichloro-1-phenylethanol combining this oxidation with an alcohol dehydrogenase-catalyzed bioreduction.