As. Pawar et S. Chattopadhyay, EXPEDIENT SYNTHESIS OF QUADRILURE ANTIPODES, THE PHEROMONE OF SQUARE-NECKED GRAIN BEETLE, Tetrahedron : asymmetry, 6(2), 1995, pp. 463-468
Both the enantiomers of the title pheromone, (E)-3-methyl-7-acetoxynon
-3-ene (I) have been synthesized in high enantiomeric excess via a ste
reoselective route. Thus, easily accessible, 3-methylpent-1-en-3-ol (2
) was converted via a Claisen orthoester rearrangement to the ester (3
) with exclusive (E)-geometry. Its derivatization to the aldehyde (5)
followed by reaction with ethylmagnesium bromide gave the racemic pher
omone alcohol (6) in 27.7% overall yield. Its enantioselective lipase
catalyzed trans-esterification directly afforded (R)-I, while its anti
pode was obtained from the resolved alcohol by chemical acetylation.