[66530-06-1]  · C4H7Al  · Ethynyldimethylaluminum  · (MW 82.08)

(conjugate addition of ethynyl groups to enones1,2)

Alternate Name: dimethylaluminum acetylide.

Solubility: sol ether.

Preparative Method: from Lithium Acetylide and Dimethylaluminum Chloride.1

Handling, Storage, and Precautions: generated in situ and used directly.

Conjugate Addition of Acetylides to a,b-Enones.

Ethynyldimethylaluminum and its derivatives are useful reagents for the 1,4-addition of alkynyl groups to a,b-unsaturated ketones (eq 1).1,2 The complex formed by reaction of Nickel(II) Acetylacetonate and Diisobutylaluminum Hydride (1:1) catalyzes the conjugate addition of the alkynyl unit of dialkylaluminum acetylides to both s-cis and s-trans enones. A low yield is obtained for direct addition of dimethylaluminum acetylide (R = H) to a,b-enones. This conjugate adduct is destroyed over a relatively short period of time in the presence of the nickel species due to side reactions involving the product, a terminal alkyne.

1. Hansen, R. T.; Carr, D. B.; Schwartz, J. JACS 1978, 100, 2244.
2. Schwartz, J.; Carr, D. B.; Hansen, R. T.; Dayrit, F. M. JOC 1980, 45, 3053.

Takeshi Nakai & Katsuhiko Tomooka

Tokyo Institute of Technology, Japan

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