Monday 5 January 2015

Oppenauer oxidation



method for selectively oxidizing secondary alcohols to ketones.


                                   

The Oppenauer oxidation is an organic reaction used to convert a primary or secondary alcohol to a ketone using another excess ketone reagent (such as acetone) and an aluminium triisopropoxide catalyst. The mechanism begins with the alcohol replacing one of the isopropoxide groups on the aluminum to generate isopropanol. Acetone then coordinates to the aluminum complex and a rearrangement reaction occurs which includes a hydride transfer from the alcohol to acetone. This process, which oxidizes the alcohol and reduces the acetone, results in the formation of the final ketone product and regeneration of the aluminum triisopropoxide catalyst




Oppenauer oxidation reaction scheme

The reaction is the opposite of Meerwein-Ponndorf-Verley reduction. The alcohol is oxidized with aluminium isopropoxide in excess acetone. This shifts the equilibrium toward the product side.



examples








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