Oriental hornet pheromone

Rj-S-Hexadecanolide (27) is the pheromone produced by the queens of the oriental hornet (Vespa orientalis). Yamamoto synthesized (R)-27 by employing an interesting asymmetric process (A—>B) followed by a multi-step conversion of B to (R)-27 via C (Scheme 40) [65]. 

Chiral lactones. The aldol type condensation of this reagent with an aldehyde has been used to synthesize two chiral five- and six-membered lactones in > 80% ee. The synthesis of the six-membered lactone (R)-( + )-d-n-hexadecanolactone (5), a pheromone of the Oriental hornet, from the /-butyl ester (1) of the sulfoxide is formulated in equation (I).1... 

Queen Substance. The queens of many hymenopterous species release primer pheromones in the colonial milieu and these compounds strongly influence the reproductive or endocrine systems of the workers. Butler et al. (139) identified ( )-9-oxo-2-decenoic as the compound that inhibits both ovarian development in workers (140) and queen cell construction (141). The queen substance of the Oriental hornet has been identified as 6-hexadecalactone (XXXVII) (142). 

Hexadecanolactone (15), a pheromone responsible for social behaviour of the oriental hornet Vespa orientalis, was prepared as illustrated in Scheme 4.9. The natural product was obtained in 64% yield with an ee of 99%. 

Enantiomerically pure lactonic pheromones 607-611, of the carpenter bee, blacktailed deer, Japanese beetle, rove beetle, and Oriental hornet, respectively, have been synthesized from racemic cyano alcohols of type 612. The key to the success of the overall approach is the facile separation of diastereomeric carbamates derived from cyano alcohols of type 612 by automated multigram LC. The chosen approach also facilitates the assignment of absolute configurations to the lactone enantiomers and their precursors. In the case of 607, direct determination of enantiomeric purity and absolute configuration is also possible using the chiral solvating agent 2,2,2-trifluoro-l-(9-anthryl)ethanol [439]. 

The synthesis of the 5-lactone, (-t-)-goniopypyrone 61, has been reported independently by Shing and Honda , starting from D-g/ycero-D-gu/o-heptono-y-lactone and D-mannitol respectively. The Japanese group also applied their chemistry to the synthesis of 62a/b and 63. Reductive elimination of an acetonide has been exploited in a synthesis of y-lactone 65, a pheromone of the oriental hornet Vespa orientalis (Scheme 11). ... 

---