Reduction of Carbonyl Groups to Methylene Groups
Wolff-Kishner Reduction: Experimental Procedure
The Wolff-Kishner reduction is used in preparative chemistry for the reduction of ketone carbonyl groups to the corresponding methylene groups. Additionally, the reaction is being used for the selective reduction of oxocarboxylic acids because carboxyl groups are not affected.
In the original version, ketone and hydazine hydrate are reacted to form the hydrazone which in turn is heated to 200 in an autoclave in the presence of sodium or sodium alkoxide.
Since the seminal report, the original procedure has been substituted by the simpler and less expensive Huang-Minlon modification. In this procedure, the ketone is reacted in the cold with an aqueous hydrazine hydrate solution in ethylene glycol followed by heating under reflux.