9.11- Dodecadien-l-yl acetate

Anion (64) generally reacts with carbonyl compounds at the y-position, whereas it reacts with alkyl halides at the a-position. The triethylaluminum ate complex of (64) exhibits reversed regioselectivity propanal and 2-methylpropanal give exclusively the a-adducts. The anti isomers are produced predominantly. Organic halides and trimethylsilyl chloride do not react with the aluminum ate complex. 9,11-Dodecadien-l-yl acetate, a pheromone of Diparopsis castanea, is prepared by condensation of 9-oxonon-l-yl acetate via the ate complex (Scheme 43). 

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