Japanese beetle japonilure

Enantiomerically pure japonilure [(4JR,5Z)-5-tetradecen-4-olide, 26] is commercially important to attract the Japanese beetle (Popillia japonica), because only pure (4.R,5Z)-26 is bioactive, while ( )-26 is totally inactive. Synthesis of (4 ,5Z)-26 via enzymatic resolution of racemic intermediates was first reported by Sugai [63], and then further studied by Fukusaki [64] to establish the process as summarized in Scheme 39. Lipase PS (Amano) from Pseudomonas sp. and lipase OF (Meito) from Candida cylindracea were shown to be the enzymes of choice. 

Fig. 10 TLC plate showing degradation of (R)- and (S)-japonilure (upper spots) by esterases from the legs (Leg) and antennae (Ant) of the Japanese beetle. The corresponding hydroxy-acids appear as lower bands. Note the slower degradation of the behavioral antagonist, (S)-japonilure, by sensillar esterase(s) from the antennae. Neither (R)- nor (S)-japonilure is degraded in control experiments (data not shown) under the same conditions, i.e., with the compounds incubated in buffer without Japanese beetle tissue extracts...

Females of several species use (R)-5-[(lZ)-l-octenyl]oxacyclopentan-2-one, buibuilactone 69 [ 140-144]. The first y-lactone identified from a scarab beetle was (R)-5-[(Z)-l-decenyl]oxacyclopentan-2-one, japonilure 70, the female produced sex pheromone of the Japanese beetle Popillia japonica [145]. Both 69 and 70 are components of specific blends of several species [140-143]. The Japanese beetle is extremely sensitive to the non-natural enantiomer of his pheromone as little as 1% of the (S)-enantiomer inhibits the attractiveness of the pheromone [ 145]. With respect to species discrimination, this is particularly... 

Japonilure R), the sex pheromone of the female Japanese beetle. Papilla japonica and its enantiomer, (5)-(+)-(5Z )-tetradecen-4-olide, which is the pheromone of the Osaka beetle, Anomala osakana have been synthesized using a highly convergent procedure and in satisfactory overall yields. 

It is not only drugs that have to be manufactured enantiomerically pure. This simple lactone is the pheromone released by Japanese beetles (Popilia japonica) as a means of communication. The beetles, whose larvae are serious crop pests, are attracted by the pheromone, and synthetic pheromone is marketed as Japonilure to bait beetle traps. Provided the synthetic pheromone is the stereoisomer shown, with the Zdouble bond and the R configuration at the stereogenic centre, only 25 jug per trap catches thousands of beetles. You first met this compound in Chapter 32, where we pointed out that double bond stereocontrol was important since the -isomer of the pheromone is virtually useless as a bait (it retains only about 10% of the activity). Even more important is control over the configuration at the chiral centre, because the S-enantiomer of the pheromone is not only inactive in attracting the beetles, but acts as a powerful inhibitor of the R-enantiomer—even 1% S-enantiomer in a sample of pheromone destroys the activity. 

R,5Z)-Japonilure r Mrt iKj. jl k Japanese beetle FopWia Japonica) S Enzymatic resolution (Lipase PS) of racemates [169] [170]... 

Studies on the degradation of enantiomers of japonilure by extracts from tissues of scarab beetles indicate that antennae-specific esterase(s) fi om the Japanese beetle showed a significant preference for the pheromone, (/ )-japonilure, over the behavioral antagonist. 

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