Synthesis and bioassay of racemic and chiral trans-alpha-necrodyl isobutyrate, the sex pheromone of the grape mealybug Pseudococcus maritimus.
A concise synthesis of the racemic form of the female-produced pheromone of the grape mealybug was developed. The synthesis was readily adapted to production of both enantiomers of the pheromone via lipase-catalyzed kinetic resolution of an intermediate in the synthesis. Replicated field trials revealed that, contrary to a preliminary report, the (R,R)- rather than the (S,S)-enantiomer is the attractive stereoisomer. Lithium aluminum hydride reduction of the insect-produced compound to alpha-necrodol followed by analysis on a chiral stationary phase GC column showed that the insect-produced material was actually an 85:15 mixture of the (R,R)- and (S,S)-enantiomers. The racemic form of the pheromone was highly attractive to male mealybugs, and in one of two field bioassays, the racemic material was significantly more attractive than the pure (R,R)-enantiomer, suggesting that the (S,S)-enantiomer might act synergistically.
Zou
Yunfan
Y
Department of Entomology, University of California, Riverside, California 92521, USA.
Daane
Kent M
KM
Bentley
Walt J
WJ
Millar
Jocelyn G
JG
D000818:Animals; D001681:Biological Assay; D002087:Butyrates / Q000138:chemical synthesis* / Q000494:pharmacology*; D005260:Female; D007313:Insecta; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D012724:Sex Attractants; D013237:Stereoisomerism
D002087:Butyrates; D012724:Sex Attractants; C550957:trans-alpha-necrodyl isobutyrate