Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2004
Publication Date: 4/27/2004
Citation: Khrimian, A., Oliver, J.E., Hahn, R.C., Dees, N.H., White, J., Mastro, V.C. 2004. Improved synthesis and deployment of (2s,3r)-2-(2'z,5'z-octadienyl)-3-nonyloxirane, a pheromone of the pink moth, Lymantria mathura. Journal of Agriculture and Food Chemistry. 52(10):2890-2895. Interpretive Summary: The pink moth, also known as the rosy Russian moth, is a widespread defoliator of different kinds of hardwood forest and orchard trees in Asia. Female pink moths are readily attracted to artificial lights, and they and their egg masses have been detected on ships originating from Asian seaports bound for the United States and Canada. Thus, this moth is a potentially devastating pest because newly hatched larvae may find habitats favorable for establishment and development in the absence of natural enemies. Traps baited with pink moth pheromone which was identified and synthesized earlier but is commercially unavailable; can play a critical part in monitoring for the accidental introduction of this potential invasive species at U.S. ports of entry. We conducted two new syntheses of the pheromone of the pink moth, one of which conveniently provided the desired mixture of products in high overall yield. The resulting composition mimics the natural pheromone and demonstrated the best attractiveness in field trials. The Animal and Plant Health Inspection Service, USDA, is considering using this synthetic pheromone as a standard detection tool for pink moth, and the synthetic method may be of interest to pheromone chemists.
Technical Abstract: We report two new syntheses of (2S,3R)-2-(2'Z,5'Z-octadienyl)-3-nonyloxirane, a sex pheromone component of the pink moth, Lymantria mathura. The key element in the first route was the construction of (Z,Z)-1-bromo-1,4-heptadiene (6) which was coupled in the final step with 2-iodomethyl-3-nonyloxirane 4 via a Grignard reaction. The second approach employed alkylation of 1,4-heptadiynyl lithium with epoxy triflates 7 in ether/hexane and delivered the pheromone in '37% overall yield from alcohol 2. The ~4:1 ratio of pheromone enantiomers, the most attractive to pink moth males, can be directly crafted from appropriately selected Sharpless asymmetric epoxidation conditions.