Determination of the Stereochemistry of the Aggregation Pheromone of Harlequin Bug, Murgantia histrionica

Abstract

Preparation of a complete stereoisomeric library of 1,10-bisaboladien-3-ols and selected 10,11-epoxy-1-bisabolen-3-ols was pivotal for the identification of the aggregation pheromone of the brown marmorated stink bug, Halyomorpha halys. Herein, we describe syntheses of the remaining 10,11-epoxy-1-bisabolen-3-ols, and provide additional evidence on the assignment of relative and absolute configurations of these compounds by single-crystal X-ray crystallography of an intermediate, (3S,6R,7R,10S)-1-bisabolen-3,10,11-triol. To demonstrate the utility of this stereoisomeric library, we revisited the aggregation pheromone of the harlequin bug, Murgantia histrionica, and showed that the male-produced pheromone consists of two stereoisomers of 10,11-epoxy-1-bisabolen-3-ol. Employment of eight cis-10,11-epoxy-1-bisabolen-3-ol stereoisomeric standards, two enantioselective GC columns, and NMR spectroscopy enabled the identification of these compounds as (3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol and (3S,6S,7R,10R)-10,11-epoxy-1-bisabolen-3-ol, which are produced by M. histrionica males in 1.4:1 ratio.

The Role of (E)-2-octenyl Acetate as a Pheromone of Bagrada hilaris (Burmeister): Laboratory and Field Evaluation

“…Moreover, in other pentatomid bugs, male-produced compounds act as sex pheromones attracting only females, such as in Piezodorus guildinii (Westwood) [32], T. pallidovirens [33], Oebalus poecilus (Dallas) [34], Eysarcoris parvus (Uhler) [35], and Pallantia macunaima (Grazia) [36]. In other cases, the male-produced compounds act as aggregation pheromones, attracting females, males, and even nymphs, such as in Murgantia histrionica (Hahn) [37,38], N. viridula [27], Eysarcoris lewisi (Distant) [39], Euschistus tristigmus (Say) [18,30], and H. halys [40].…”

A Transcriptome Survey Spanning Life Stages and Sexes of the Harlequin Bug, Murgantia histrionica

“…In a laboratory setting, Zahn et al [11,12] showed that an aggregation pheromone emitted by adult males feeding on a plant host was attractive to both sexes of adults, and concluded that the pheromone was a single isomer of 10,11-epoxy-1-bisabolen-3-ol [4-[3-(3,3-dimethyloxiran-2-yl)-1-methylpropyl]-1-methylcyclohex-2-en-1-ol], dubbed murgantiol. Khrimian et al [13] showed that the pheromone consisted of two stereoisomers, (3 S ,6 S ,7 R ,10 S )- and (3 S ,6 S ,7 R ,10 R )-10,11-epoxy-1-bisabolen-3-ol, which occur in a ~1.4:1 ratio in emissions of adult male harlequin bug. Weber et al [14] demonstrated that, in the field, lures containing a synthetic eight-stereoisomer blend were of comparable attractiveness with pure pheromone components to both sexes in adults, as well as to nymphs, and that presence of a host plant (collard) increased this attractiveness.…”

Expedient synthesis of bisabolenol stink bug pheromones via stereodefined cyclohex-2-enones

“…17 Intrigued by a significant mitigation of the loss of enantiopurity when KOH/Bu 4 NOH was replaced by LiOH/iPrOH (89% ee, or 94.5:5.5 S/R), 17 we became interested in using this base system for cyclizations of ketoaldehydes 8 and 9. Thus, stirring aldehydes 8 and 9 in an 10% isopropanol solution of lithium hydroxide hydrate at 25 o C for 5 h proceeded without significant epimerization and provided ketones 6 and 7 in 66% and 67% yields, respectively, and 92:8 dr (SM=Supplementary Material, p. [6][7][8]. We also found that lithium hydroxide hydrate as a source of LiOH provided a more reproducible and better stereochemical output than anhydrous lithium hydroxide, and the cyclization is facilitated by an initial ultrasonication.…”

“…9 This conveniently provided two single stereoisomers from one reaction (Scheme 1) and thus allowed us to build a full library of stereoisomers of bisaboladienols and epoxybisabolenols. 8,9 Scheme 1. Previous approach (Ref.…”