[1586-92-1] · C6H15AlO · Diethylaluminum Ethoxide · (MW 130.17)
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.
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.
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
Gary W. Morrow
The University of Dayton, OH, USA