Modular Stereoselective Synthesis of Sex Pheromone of Lambdina fiscellaria lugubrosa (Hulst) and Discovery of Cross-Species Attraction in Semiothisa cinerearia (Bremer & Grey)

The western hemlock looper, <i>Lambdina fiscellaria lugubrosa</i> (Hulst) is a destructive defoliator of coniferous forests and a major cause of economic losses in forestry. A novel and efficient stereoselective synthesis of the sex pheromone of the western hemlock looper (<b>1</b>, <b>2</b> and <b>3</b>) has been successfully achieved. The synthetic strategy integrates several key transformations, including Evans' chiral auxiliaries, Grignard cross-coupling, hydroboration-oxidation, sulfone alkylation, and hydrogenation, providing an efficient and scalable approach for sex pheromone production. The three synthesized pheromone components were subsequently tested for their ability to attract <i>Semiothisa cinerearia</i> (Bremer & Grey) using both Y-tube and cage bioassays. Notably, compound <b>1</b> exhibited a cross-species attractive effect on <i>S. cinerearia</i>, a species that had not previously been documented to respond to the pheromone of <i>L. fiscellaria lugubrosa</i>. This discovery underscores the potential for cross-species attraction, broadens our understanding of pheromone specificity, and emphasizes the value of stereoselectively synthesized pheromones as molecular tools for cross-species pest monitoring and integrated pest management.