Diethylaluminum Ethoxide1

Et2AlOEt

[1586-92-1]  · C6H15AlO  · Diethylaluminum Ethoxide  · (MW 130.17)

(base for aldol condensations;2 reducing agent for preparation of Ni catalysts3)

Physical Data: colorless liquid; dimeric structure; mp 2.5-4.5 °C; bp 108-109 °C/10 mmHg; d 0.850 g cm-3.

Solubility: sol hydrocarbons and ether.

Form Supplied in: commercially available, usually as a 25% solution in toluene.

Handling, Storage, and Precautions: the reagent itself is pyrophoric and its solutions are highly flammable and air and moisture sensitive and should be handled under an inert atmosphere. Use in a fume hood.

Aldol Condensations.

Diethylaluminum ethoxide is a useful base for promoting intramolecular aldol condensations in highly hindered systems. Thus 10 equiv of the reagent in toluene solution are used for effecting the condensation of polycyclic diketones (eqs 1 and 2).2 Other bases fail to give any appreciable amount of the corresponding cyclization products.

Reducing Agent.

When used to reduce Ni(acac)2 to Ni0, the reagent gives a selective catalyst for the [4 + 4] cyclodimerization of pentadienoic acid esters in the presence of 1,3-butadiene (eq 3).3 Use of other reducing agents gives lower selectivity and greater amounts of [4 + 2] products.

The reagent has also been used as a cocatalyst for terminal alkene isomerizations.4


1. Hirabayashi, T.; Sakakibara, T.; Ishii, Y. JOM 1972, 35, 19.
2. ApSimon, J. W.; Lawuyi, R. F. SC 1987, 17, 1773.
3. Brun, P.; Tenaglia, A. J. Mol. Catal. 1991, 70, L1.
4. Cavell, K. J.; Chan, K. Y.; Peacock, E. J.; Ridd, M. J., Davies, N. W. AJC 1991, 44, 171.

Gary W. Morrow

The University of Dayton, OH, USA



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