Diethylaluminium cyanide

Diethylaluminum cyanide ("Nagata's reagent")[2] is the organoaluminum 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.[1][3][4][5][6]

Diethylaluminium cyanide
Names
IUPAC name
diethylalumanylformonitrile
Other names
Cyanodiethyl Aluminum
(cyano-κC)diethyl-Aluminum
(cyano-C)diethyl-Aluminum
Cyanodiethyl-(7CI,8CI) Aluminum
Cyanodiethylallane
Cyanodiethylaluminum
Diethylaluminum Cyanide
Identifiers
ECHA InfoCard 100.024.873
Properties
C
4H
10AlCN
Et
2AlCN
Molar mass 111.12 g mol−1
Appearance dark brown, clear liquid (1.0 mol L−1 in toluene)[1]
Density 0.864 g cm−3 at (25 °C) liquid
Boiling point 162 °C (324 °F; 435 K) at 0.02 mmHg
Benzene, Toluene, diisopropyl ether
Hazards
Flash point 7 °C (45 °F; 280 K) closed cup[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Synthesis

Diethylaluminum cyanide was originally generated by treatment of triethylaluminum 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.

Et3Al + HCN → 1/n (Et2AlCN)n + EtH

Structure

Diethylaluminum cyanide has not been examined by X-ray crystallography, although other diorganoaluminum cyanides have been. Diorganylaluminum 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 diethylaluminum 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:[4]

Bis(tert-butyl)aluminium cyanide, tBu2AlCN exists as a tetramer in the crystalline phase:[7][8]

Uses

Diethylaluminum 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] The purpose of this reaction is to generate alkylnitriles, which are precursors to amines, amides, carboxylic acids esters and aldehydes.

References
  1. "MSDS - 276863". Sigma-Aldrich. Retrieved December 9, 2012.
  2. Nagata, W (1988). "Diethylaluminum cyanide". Organic Syntheses. VI: 307. doi:10.15227/orgsyn.052.0090.
  3. Nagata, W. (1966). "Alkylaluminum cyanides as potent reagents for hydrocyanation". Tetrahedron Lett. 7 (18): 1913–1918. doi:10.1016/S0040-4039(00)76271-X.
  4. Uhl, Werner; Schütz, Uwe; Hiller, Wolfgang; Heckel, Maximilian (1995). "Synthese und Kristallstruktur des trimeren [(Me3Si)2CH]2Al—CN". Z. anorg. allg. Chem. 621 (5): 823–828. doi:10.1002/zaac.19956210521.
  5. Wade, K.; Wyatt, B. K. (1969). "Reactions of organoaluminium compounds with cyanides. Part III. Reactions of trimethylaluminium, triethylaluminium, dimethylaluminium hydride, and diethylaluminium hydride with dimethylcyanamide". J. Chem. Soc.: 1121–1124. doi:10.1039/J19690001121.
  6. Coates, G. E.; Mukherjee, R. N. (1963). "35. Dimethylaluminium cyanide and its gallium, indium, and thallium analogues; beryllium and methylberyllium cyanide". J. Chem. Soc.: 229–232. doi:10.1039/JR9630000229.
  7. Uhl, W.; Matar, M. (2004). "Hydroalumination of nitriles and isonitriles" (PDF). Z. Naturforsch. B. 59 (11–12): 1214–1222.
  8. Uhl, W.; Schütz, U.; Hiller, W.; Heckel, M. (2005). "Synthese und Kristallstruktur des trimeren [(Me3Si)2CH]2Al—CN" (PDF). Z. Naturforsch. B. 60 (2): 155–163.
  9. Nagata, W.; Yoshioka, M. (1988). "Diethylaluminum cyanide". Organic Syntheses.; Collective Volume, 6, p. 436
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