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Conventional hydrocyanation catalysts, e.g. Ni(P(OR) 3) 4, catalyse the formation of racemic mixtures. When however the supporting ligands are chiral, the hydrocyanation can be highly enantioselective. For asymmetric hydrocyanation, popular chiral ligands are chelating aryl diphosphite complexes. [1] [2] [3]
The conversion, which is called hydrocyanation, employs nickel complexes as catalysts. [18] RCH=CH 2 + HCN → RCH 2 −CH 2 CN. Four molecules of HCN will tetramerize into diaminomaleonitrile. [19] Metal cyanides are typically prepared by salt metathesis from alkali metal cyanide salts, but mercuric cyanide is formed from aqueous hydrogen ...
Diethylaluminium cyanide is used for the stoichiometric hydrocyanation of α,β-unsaturated ketones. The reaction is influenced by the basicity of the solvent. This effect arises from the Lewis acidic qualities of the reagent. [9]
In the final stage, these pentenenitriles are subjected to a second hydrocyanation to produce adiponitrile, [4] the anti-Markovnikov product, as well as 2-methylglutaronitrile, a useful byproduct. Another side reaction is the alkene metathesis of 3-pentenenitrile to yield dicyanobutenes, which are readily hydrogenated to adiponitrile as ...
To replace the use of toxic hydrocyanide (HCN) gas or surrogates such as acetone cyanohydrin, Bill Morandi and co-workers developed a hydrocyanation strategy using shuttle catalysis. [10] In this example, they use isovaleronitrile as a HCN surrogate under nickel/aluminum co-catalyzed conditions to afford hydrocyanation reactions of various alkenes.
The two phosphorus atoms (orange) of dppe have a bite angle of 85.8° on the palladium atom (blue) in [PdCl 2 (dppe)].. In coordination chemistry, the bite angle is the angle on a central atom between two bonds to a bidentate ligand.
Asymmetric Hydrocyanation The RajanBabu group developed methodology in the area of hydrocyanation , leveraging the reaction of vinylarenes with HCN in the presence of Ni(0) complexes. Based on the phosphorus ligands within the Ni complex, the reaction can be rendered asymmetric.
Hydrocyanation is an industrial method for producing nitriles from hydrogen cyanide and alkenes. The process requires homogeneous catalysts. An example of hydrocyanation is the production of adiponitrile, a precursor to nylon-6,6 from 1,3-butadiene: CH 2 =CH−CH=CH 2 + 2 HC≡N → NC(CH 2) 4 C≡N