Determination of the enantiomeric composition of several insect pheromone alcohols

Semiochemicals in the Natural History of Southern Pine Beetle Dendroctonus frontalis Zimmermann and Their Role in Pest Management

“…Given that most of the female's large "store" of trans-verbenol appears to be released before entry into the bark, it is possible that trans-verbenol may play a more important role in close-range interactions by beetles on the bark surface (Bunt et al, 1980) rather than or in addition to functioning as a longrange component of the aggregation pheromone. The enantiomeric ratio produced by females has been measured as 60:40 and 25:75 (+)/(À) (Grosman et al, 1997;Plummer et al, 1976), although this ratio is likely influenced by the enantiomeric composition of α-pinene of the host tree. In the mountain pine beetle, D. ponderosae, trans-verbenol is the major component of the aggregation pheromone released by solitary females attacking a host and acts synergistically rather than redundantly with host odours Skillen et al, 1997).…”

Insect Pheromones: A Critical Review of Recent Advances in Their Chemistry, Biology, and Application

“…Complex molecules often produce spectra with overlapping peaks, thus making interpretation difficult. In some cases, this problem can be alleviated by use oflanthanide shift reagents such as Eu(fod)3 (45). Chiral shift reagents have been used to determine the enantiomeric composition of several pheromone bicyclic ketals (150, 195, 303a) (46) and alcohols (1, 229, 232, 266a, 294a) (45) (see Chart I).…”

“…In some cases, this problem can be alleviated by use oflanthanide shift reagents such as Eu(fod)3 (45). Chiral shift reagents have been used to determine the enantiomeric composition of several pheromone bicyclic ketals (150, 195, 303a) (46) and alcohols (1, 229, 232, 266a, 294a) (45) (see Chart I). The cx-methoxy-cx-trifluoromethylphenylacetyl derivatives of these alcohols were also used to determine enantiomeric composition (45,47,48).…”

“…Chiral shift reagents have been used to determine the enantiomeric composition of several pheromone bicyclic ketals (150, 195, 303a) (46) and alcohols (1, 229, 232, 266a, 294a) (45) (see Chart I). The cx-methoxy-cx-trifluoromethylphenylacetyl derivatives of these alcohols were also used to determine enantiomeric composition (45,47,48). It is interesting to note that (266a) from Ips pini and (294a) from Scolytus multistriatus are 100% (-)-enantiomers, whereas, (229) from Gnathotrichus sulcatus is a 65: 35 mixture of (+)/(-), (232) from Dendroctonus frontalis is 60: 40 (+)/(-), and (1) from Dendroctonus pseudotsugae is 50: 50 (+)/(-).…”

“…The mechanism for the intraspecific variation in pheromone systems of I. pini described by LANIER et al (329) seems partially resolved. PLUMMER et al (45) found that the natural en anti orner composition of ipsdienol for I. pini from Idaho to be 100% (-). The European fir engraver, Pityokteines curvidens, aggregates only in response to the S-( -)-isomer of ipsenol, and the R-( + )-isomer is inactive (330).…”