Vespa orientalis

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]. 

The palatability of the flesh of birds to humans is broadly correlated with their visibility, including plumage color and behavior. Cott (1947) noted in Egypt that hornets Vespa orientalis) fed on a carcass of a dove but ignored that of a kingfisher... 

Removal of the auxiliary group from 12 (see p413) to give 13 followed by several steps yields (-)-(65)-tetrahydro-6-undecyl-2//-pyran-2-one (14), a pheromone of the wasp Vespa orientalis. Comparison of the optical rotation of the synthetic product with that of the natural product served to confirm the stereochemistry of the initial reduction to 12. 

R,6R) diastereoisomer (Scheme 7). Again, from 34 the (5R,6R) product 43 was obtained. Products 42 and 43 represent the two enantiomers of the proposed major component of a mosquito oviposi-tion attractant pheromone (18). The enantiomeric forms of 5-hexadecanolide, 44 and 45, the pheromone of Vespa orientalis, were obtained from the enantiomeric aldehydes 34 and 37 (19). All the compounds obtained up to this point have been prepared in both enantiomeric forms, starting from a single chiral material. 

Synthetic Applications. (5 )-Dihydro-5-(hydroxymethyl)-2(3H)-furanone (2) was first described in 1971 as an intermediate in the synthesis of o-ribose from r-glutamic acid. Since then, this lactone and its (f )-enantiomer have found widespread use as chirons for constructing a rich variety of natural products ranging from simple pheromones to complex macrocycles and ionophore antibiotics. The chemical manipulation of these chirons often involves lactone cleavage at an early stage, - - as illustrated by the preparation of suitable intermediates for the synthesis of the Vespa orientalis pheromone (R)-S-n-hexadecanolactone (14) (eq 4), the antiviral fungal metabolite brefeldin A (15) (eq 5), and (7aa)-cp/-hemibrevetoxin B (16) (eq 6). ... 

Kinetic resolution of chiral acetals has been effected by use of some organoaluminum reagents [84], On treating a chiral acetal 88, derived from (2, 4/ )-(-)-pentanediol, with -Bu3A1 at room temperature, one diastereomer was found to react much faster than the other, and the residu enol ether is transformed into optically pure ketone. The efficiency of this method is demonstrated by a concise synthesis of (5)-(-)-5-hexadecan-l,5-lactone (89), the pheromone of Vespa orientalis, as shown in Sch. 56. 

S)-5- hcxadccanolidc O A, %fc TI, l D Oriental hornet (Vespa orientalis) R Grubbs Uletin methatesis [1561... 

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%. 

Hyaluronidase has been shown to be present in crude extracts of the testes of honey bees Apis mellifera) and oriental hornets (Vespa orientalis). The enzyme hydrolysed hyaluronic acid and chondroitin 6-sulphate (pH optimum 4.5—5.0 for both substrates), and its activity increased throughout the temperature range 37—45 °C (cf. bovine and ovine testicular hyaluronidases, which are gradually deactivated). 

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). ... 

Coke and Richon have constructed the 8-lactone framework of n-hexadecalactone, the proposed pheromone isolated from Vespa orientalis, through lactonization of a hydroxy acid intermediate [39] (Scheme 3). The optically pure amino alcohol 22 obtained by resolution was converted to the optically active epoxide 23 by quatemization, followed by Hofmaim elimination. Addition of the dianion of propiolic acid to epoxide 23, and subsequent reduction of the resulting acetylenic hydroxy acid with hydrogen and palladium, provided the saturated hydroxy acid 25, which spontaneously cycUzed to afford 8-lactone 12. In a similar way, the enantiomer of amino alcohol 22 was also transformed into the antipode of lactone 12. Furthermore, using this method, any terminal epoxide can easily be converted to the corresponding saturated 8-lactone in two steps. 

Scheme 3 Coke and Richon synthesis of the proposed pheromone from Vespa orientalis...

Vespa orientalis, the Oriental hornet, produces lactone (428) (Scheme 77), which is thought 183) to control some aspects of social behavior. The / -(+)- and 5-(-)-enantiomers (428a and 428b, respectively) were elaborated by Coke and Richon 184) from 1-tridecene (422) via amino-alcohol (424), which was resolved into its enantiomeric forms by resolution of the optically active dibenzoyl tartarates (Scheme 77). Hofmann elimination followed by reaction with propiolic acid dianion (425) and reductive cyclization completed the synthesis. 

Coke, J. L., and A. B. Richon Synthesis of optically-active 8- -hexadecalactone, the proposed pheromone from Vespa orientalis. J. Org. Chem. 41, 3516—3517 (1976). 

The sequences of two proteins from Vespa orientalis venom claimed to be lysophos-pholipase and phospholipase A2 have been reported (77). Comparison of the sequence reported for the 152 amino acid lysophospholipase with that of Vespa crabro phospholipase AiB indicates that it is the N-terminal 73 residues, residues 119-133, some of the C-terminal section fragments and the rest is not clearly related. Similar analysis of the reported structure of the 139 amino acid phospholipase A2 shows that it consists of the N-terminal 49 residues, residues 119-133, and some fragments of the C-terminus of phospholipase A B the rest is unrelated. It is probable that these reported sequences are fragments of the intact venom phospholipase, and not different proteins. The sequence data reported for these enzymes is not consistent with that found for other vespid venom phospholipases. 

Komian, S.H., Jabbour, S., and Harari, M.D., 1990, Multiple hornet ( Vespa orientalis) stings with fatal outcome in a child. J. Paediat. C. 26 283-285. 

Vesor, A.S., Korneev, Sh.I., Salikhov andTuichibaev, M.U., 1989, [Amino acid sequence of orientotoxins I and II from the venom of the hornet Vespa orientalis], Bioorg. Khim. 15, 127-9. 

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