TheWolff‐Kishner Reduction

Abstract

The oxygen atom of the carbonyl group in aldehdyes and ketones can be replaced by hydrogen by heating the semicarbazone, the hydrazone, or the azine in the presence of an alkaline catalyst. This reaction is known as the Wolff‐Kishner reduction. Two slightly different variations of the method were discovered independently by Kishner in 1911 and by Wolff in 1912. Though the Kishner method has the advantage of avoiding the necessity of a sealed tube, the Wolff method has been modified to obviate both this necessity and that of isolating the intermediate carbonyl derivative. This reduction is the subject of this chapter.

Iridium‐Catalyzed Direct Dehydroxylation of Alcohols

“…For this matter, we planned to take advantage of the better reactivity of carbonyl compounds, which can be generated in situ by oxidation of alcohols using transition‐metal catalysts. Compatible with this process is the Wolff–Kishner reduction, a classical textbook reaction, representing a powerful synthetic strategy to deoxygenate carbonyl groups in organic compounds 8. We envisaged that by employing hydrazine as a nucleophilic reducing reagent in addition a suitable transition‐metal catalyst, the oxidation of alcohols might be combined with the Wolff–Kishner reduction to enable the direct dehydroxylation of alcohols.…”

Bimetallic Nanoparticles in Supported Ionic Liquid Phases as Multifunctional Catalysts for the Selective Hydrodeoxygenation of Aromatic Substrates

“…However, the large‐scale synthetic application of this transformation has been hindered by the lack of suitable catalysts that allow for selective catalytic hydrodeoxygenation of aromatic ketones without concomitant hydrogenation of the aromatic ring (Scheme ) . Stoichiometric methods such as the Clemmensen and Wolff–Kishner reductions often remain the methods of choice for the removal of carbonyl moieties from aromatic substrates, despite the fact that they rely on the use of toxic reagents and/or create large amounts of undesired and problematic waste . Current synthetic pathways involving the hydrodeoxygenation of aromatic substrates cannot fulfill the requirements of high yields, selectivity, stability, productivity, safety, and environmental compatibility .…”

Polymethylhydrosiloxane reduction of carbonyl function catalysed by titanium tetrachloride

“…Various methods have been employed for this chemical transformation but the Clemmensen [1] and Wolff-Kishner [2] reduction processes have thus far exhibited the most general utility [3]. However, the drastic reaction conditions of both processes have given rise to various other methods, all in an effort to find milder reaction conditions.…”