Diethylaluminium cyanide explained

Diethylaluminium cyanide ("Nagata's reagent")^[1] is the organoaluminium compound with formula . This colorless compound is usually handled as a solution in toluene. It is a reagent for the hydrocyanation of α,β-unsaturated ketones.^{[2] [3] [4] [5]}

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:^[6]

Notes and References

1. Nagata. W. Diethylaluminum cyanide. Organic Syntheses. 1988. VI. 307. 10.15227/orgsyn.052.0090.
2. Web site: MSDS - 276863. Sigma-Aldrich. December 9, 2012.
3. Nagata. W.. Alkylaluminum cyanides as potent reagents for hydrocyanation. Tetrahedron Lett.. 1966. 7. 18. 1913–1918. 10.1016/S0040-4039(00)76271-X.
4. Wade. K.. Wyatt. B. K.. Reactions of organoaluminium compounds with cyanides. Part III. Reactions of trimethylaluminium, triethylaluminium, dimethylaluminium hydride, and diethylaluminium hydride with dimethylcyanamide. J. Chem. Soc.. 1121–1124. 1969. 10.1039/J19690001121.
5. Coates. G. E.. Mukherjee. R. N.. 35. Dimethylaluminium cyanide and its gallium, indium, and thallium analogues; beryllium and methylberyllium cyanide. J. Chem. Soc.. 229–232. 1963. 10.1039/JR9630000229.
6. Synthese und Kristallstruktur des trimeren [(Me₃Si)₂CH]₂Al—CN. Werner. Uhl. Uwe. Schütz. Wolfgang. Hiller. Maximilian. Heckel. Z. anorg. allg. Chem.. 1995. 621. 5. 823–828. 10.1002/zaac.19956210521.