Sex pheromone of the pink hibiscus mealybug, Maconellicoccus hirsutus , contains an unusual cyclobutanoid monoterpene

Abstract

Two compounds that together constitute the female sex pheromone of the pink hibiscus mealybug (PHM), Maconellicoccus hirsutus , were isolated, identified, and synthesized. They are ( R )-2-isopropenyl-5-methyl-4-hexenyl ( S )-2-methylbutanoate [common name is ( R )-lavandulyl ( S )-2-methylbutanoate] and [( R )-2,2-dimethyl-3-(1-methylethylidene)cyclobutyl]methyl ( S )-2-methylbutanoate [which we refer to as ( R )-maconelliyl ( S )-2-methylbutanoate]. Maconelliol is an unusual cyclobutanoid monoterpene, and its structure has been established by enantioselective synthesis from precursors of known structure and configuration. A 1:5 synthetic mixture of the two RS esters (1 μg per rubber septum) proved to be a potent attractant of males in field bioassays. The pheromone component, maconelliyl 2-methylbutanoate, represents a heretofore undescribed natural product.