Testosterone Oppenauer oxidation

The stereochemical argument can be closed with the observation that oxidation of dehydroepiandrosterone by the Oppenauer reaction (aluminum isopropoxide in the presence of a ketone) yields the oxidation product androst-4-ene-3,17-dione (14-1) (Scheme 1.14). The same diketone is formed from oxidation of testosterone (14-2). Going in the reverse direction, androst-4-ene-3,17-dione can be converted to testosterone by treatment with fermenting yeast. 

Androsten-3/ -ol-17-one acetate is reduced over Raney nickel to the 17jS-alcohol, which is protected as a benzoate. This allows the selective hydrolysis of the acetate with methanolic sodium hydroxide solution. A final Oppenau-er oxidation leads to testosterone benzoate, hydrolysis of which gives the target compound. 

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