General Procedure for Oppenauer Oxidation under Standard Conditions

5 General Procedure for Oppenauer Oxidation Under Standard Conditions 

Finally, the organic phase that was previously washed with aqueous phases and dried (Na2S04 or MgS04) is concentrated, giving a crude residue that may need further purification. 

The alcohol in this sensitive indole could be oxidized to the desired ketone by heating with cyclohexanone and aluminium isopropoxide. A very similar substrate could no be oxidized efficiently after trying a wide variety of reagents.47 

A very mild Oppenauer oxidation using acetone and aluminium isopropoxide allows the obtention of the desired ketone, while pyridine-chromic acid or manganese dioxide produce, aromatization of the ring on the left. 

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