Oppenauer Oxidation

In 1937, R.V. Oppenauer used catalytic amounts of aluminum tert-butoxide to convert steroids with secondary alcohol functionality to their corresponding ketones. Oppenauer’s method built on research conducted by other researchers such as H. Meerwein and A. Verley, who described the reduction of carbonyl compounds using aluminum alkoxides.

Oppenauer’s method was high-yielding and mild compared to other techniques. Today, the oxidation of primary and secondary alcohols to aldehydes and ketones in the presence of metal alkoxides is known as the Oppenauer oxidation.

One unique feature of this oxidation is that secondary alcohols are oxidized much faster than primary alcohols, so complete chemoselectivity can be achieved.

The reverse reaction, the reduction of aldehydes and ketones to alcohols, is called the Meerwein-Ponndorf-Verley reaction.

The Oppenauer oxidation has been used in several total synthesis campaigns, including the synthesis of lycopodium alkaloids such as lycodoline.