Diethylaluminium cyanide

Synthesis

Diethylaluminium cyanide was originally generated by treatment of triethylaluminium with a slight excess of hydrogen cyanide. The product is typically stored in ampoules because it is highly toxic. It dissolves in toluene, benzene, hexane and isopropyl ether. It undergoes hydrolysis readily and is not compatible with protic solvents.

:

Structure

Diethylaluminium cyanide has not been examined by X-ray crystallography, although other diorganoaluminium cyanides have been. Diorganylaluminium cyanides have the general formula , and they exist as cyclic trimers (n = 3) or tetramers (n = 4). In these oligomers, one finds AlCN---Al linkages. One compound similar to diethylaluminium cyanide is bis[di(trimethylsilyl)methyl]aluminium cyanide, , which has been shown crystallographically to exist as a trimer with the following structure:

:[[File:Cyclo-(((Me3Si)2CH)2AlCN)3-2D.png|300px|trimeric bis[di(trimethylsilyl)methyl]aluminium cyanide]]

Bis(tert-butyl)aluminium cyanide, exists as a tetramer in the crystalline phase:

:[[File:Cyclo-(tBu2AlCN)4-2D.png|200px|tetrameric bis(tert-butyl)aluminium cyanide]]

Uses

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. The purpose of this reaction is to generate alkylnitriles, which are precursors to amines, amides, carboxylic acids esters and aldehydes. :[[File:Diethylaluminumcyanidehydrocyanation.png|500 px]]

References

References

1. (1988). "Diethylaluminum cyanide". Organic Syntheses.
2. "MSDS - 276863". [[Sigma-Aldrich]].
3. (1966). "Alkylaluminum cyanides as potent reagents for hydrocyanation". [[Tetrahedron Lett.]].
4. (1969). "Reactions of organoaluminium compounds with cyanides. Part III. Reactions of trimethylaluminium, triethylaluminium, dimethylaluminium hydride, and diethylaluminium hydride with dimethylcyanamide". [[J. Chem. Soc.]].
5. (1963). "35. Dimethylaluminium cyanide and its gallium, indium, and thallium analogues; beryllium and methylberyllium cyanide". [[J. Chem. Soc.]].
6. (1995). "Synthese und Kristallstruktur des trimeren [(Me₃Si)₂CH]₂Al—CN". [[Zeitschrift für anorganische und allgemeine Chemie.
7. (2004). "Hydroalumination of nitriles and isonitriles". [[Z. Naturforsch. B]].
8. (2005). "Synthese und Kristallstruktur des trimeren [(Me₃Si)₂CH]₂Al—CN". [[Z. Naturforsch. B]].
9. (1988). "Diethylaluminum cyanide".