EXPEDIENT SYNTHESIS OF QUADRILURE ANTIPODES, THE PHEROMONE OF SQUARE-NECKED GRAIN BEETLE

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.