Diethylaluminium cyanide

Diethylaluminium cyanide ("Nagata's reagent") is the organoaluminium compound with formula ((C2H5)2AlCN)_{n}. This colorless compound is usually handled as a solution in toluene. It is a reagent for the hydrocyanation of α,β-unsaturated ketones.

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.


 * n Et3Al + n HCN → (Et2AlCN)_{n} + n EtH

Structure
Diethylaluminium cyanide has not been examined by X-ray crystallography, although other diorganoaluminium cyanides have been. Diorganylaluminium cyanides have the general formula (R2AlCN)_{n}, 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, ((Me3Si)2CH)2AlCN, 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, ^{t}Bu2AlCN exists as a tetramer in the crystalline phase:


 * Cyclo-(tBu2AlCN)4-2D.png

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.
 * Diethylaluminumcyanidehydrocyanation.png