Kishner reaction

This reaction is discussed extensively in an eadier review (41). In the Huang-Minlon modification of the Wolff-Kishner reaction, a high boiling solvent such as diethylene glycol is used to achieve the required high temperatures (180—210°C) without the use of pressure equipment (42). The base is generally alkaU hydroxide or an alkoxide (43). 

The method of choice for the reduction of keto groups to methylenes remains the WolfT-Kishner reaction (2) or its modification discovered by Huang-Minlon (5). Originally, the hydrazone formation was carried out in a separate step, followed by... 

Nucleophilic Addition of Hydrazine The Wolff-Kishner Reaction 715... 

A useful variant of the imine-forming reaction just discussed involves the treatment of an aldehyde or ketone with hydrazine, H2NNH2, in the presence of KOH. Called the Wolff-Kishner reaction, the process is a useful and genera method for converting an aldehyde or ketone into an alkane, r2c=o —> R2CH2. 

Schiff base, 710 Wittig reaction, 720 Wolff—Kishner reaction, 715 yiide, 720... 

Wolff-Kishner reaction (Section 19.9) The conversion of an aldehyde or ketone into an alkane by reaction with hydrazine and base. 

Sandmeyer reaction, 943 saponification. 809-810 SN1 reaction, 373-375 Sn2 reaction, 363-364 Stork enamine reaction, 897-898 transamination, 1167 Williamson ether synthesis, 655 Wittig reaction, 720-721 Wolff-Kishner reaction, 715-716 Meerwein-Ponndorf-Verley reaction, 746... 

The first step in the mechanism of the Wolff-Kishner reaction consists of formation of the hydrazone (16-19). 

The reduction of tosylhydrazones by LiAlH4 or NaBH4 also converts carbonyl groups to methylene.277 It is believed that a diimide is involved, as in the Wolff-Kishner reaction. 

Reduction of the carbonyl group by Wolff-Kishner reaction gives intermediate 52.Treatment of that compound with butyl lithium gives the corresponding... 

Hydrogenolysis of an aldehyde or ketone carbonyl to >CH2 is an important organic transformation, and classical procedures such as the Clemmenson and Wolff-Kishner reactions have limitations (24, 25) heterogeneous catalytic systems and several two-step procedures are also known (1, 24, 26). Our observation of this conversion in what is essentially a 2-phase medium... 

This mixture is the Huang Minion modification of the Wolff Kishner reaction. In the editor s experience it often leaps from the flask with sudden gas evolution. In addition to the expected nitrogen, at the operating temperature of around 200°C it is uncomfortably near the temperature of hydrogen evolution from glycol decomposition. The reduction proceeds much cooler in dimethyl sulfoxide or some of the alkoxyethanols as solvent. 

The rearrangement of hexahydroazocino [4,3-1 ] indole 101 into pyrrolo[3,2-flj-carbazole 102 under Wolff-Kishner reaction conditions is also described in the publication (Scheme 28 84H(22)561). The reaction is a special case of cleavage of compounds related to gramine. 

Wittig reaction of azocine 214 with triphenylmethylenphosphane gives methylene derivative 215. In contrast, under Wolff-Kishner reaction conditions 214 was transformed into azocine 216a. Catalytic hydrogenation of the methylene... 

Willgerodt reaction, 3, 2 Wittig reaction, 14, 3 31 [2,3]-Wittig rearrangement, 46, 2 Wolff-Kishner reaction, 4, 8... 

Xhe transformation of the carbonyl group to methylene in ketoamine 15 (to yield 2) proceeds by means of the Wolff-Kishner reaction (59AP143). 

In the thiophene series a Wolff-Kishner reaction on the 3-aroyl compound 379, in addition to the expected reduction product, affords the pyrazole 381. A typical rearrangement of the hydrazone 380, followed... 

Scheme 15. Reaction conditions i, CH2O, Et2NH ii, EtNH2 iii, CH2=CHCOOEt iv, Na v, Wolff-Kishner reaction.

L. F. and M. Ficscr, Harvard University, Cambridge, MA. hllp //www. harvard.edu/. Reforwalsky Reaction Willgerodt Reaction and Wolff-Kishner Reaction... 

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