14 Biological Chemistry Part (ii) Insect Chemistry By R. BAKER and D. A. EVANS Department of Chemistry University of Southampton Southampton S.095NH 1 Introduction Since the last Annual Report on this topic,’ it has become increasingly apparent that the role of chemicals in the mediation of insect behaviour is immeasurably more complex than imagined earlier and that current knowledge allows us to construct only a superficial understanding of insect life. This Report selectively reviews some major advances reported in the past two years and the scope of coverage remains broadly similar to the 1975 Report. Several books articles and reviews have appeared in the meantime particularly in the areas concerned with pest management methods and plant-insect interactiom2 2 Sex Attraction and Related Phenomena The sex pheromones of moths and butterflies (Lepidoptera) have again proven to be a fruitful area of st~dy,~ and the Table lists structures from several detailed examinations.All are C12 CI4 c16 or C18straight-chain alcohols acetates or aldehydes with the exception of (la) and (Ib) from the Peach Fruit Moth Carposina niponensi~,~ and (2) and (3) .from the Potato Tuberworm Moth Phthorimaea operculella (species C in the Table) In addition to a pyrrolizidine alkaloid (4) reported earlier the hairpencil secretion of the butterfly Amauris ochlea contains inter alia methyl salicylate eugenol and cis-jasmone (5).6 In Danaus species pyrrolizidine alkaloids in food ’ R. Baker and D. A. Evans Ann. Reports (B) 1975,72,347.* ‘Animal Communication by Pheromones’ H. H. Shorey Academic Press London 1976; ‘Chemical Control of Insect Behaviour; Theory and Application’ H. H. Shorey and J. €3. McKelvey jun. Wiley New York 1977; ACS Symp. Ser. 1976 No. 23 ‘Pest Management with Insect Sex Attractants and Other Behaviour Controlling Chemicals’ (Symposium 1975); ACS Symp. Ser. 1977 No. 37 ‘Pesticide Chemistry in the 20th Century’ (Symposium 1976); Recent Adv. Phytochem. 1976,10 ‘Biochemical Interaction of Plants and Insects’; J. W. Wheeler Lloydia 1976 39 53; B. Tursch J. C. Braekman and D. Daloze Experientia 1976 32,401. ’W. L. Roelofs and R. T. Cardi Ann. Rev. Entomol. 1977 22 377; J. Weatherston and J. Percy Endeavour 1977.83. Y. Tamaki K. Honma and K. Kawasaki Appl.Entomol. Zool. 1977,12,60. C. J. Persoons S. Voerman P. E. J. Verwiel F. J. Ritter W. J. Nooijen and A. K. Minks Entomol. Exp. Appl. 1976 20 289; R. Yamaoka H. Fukami and S. Ishii Agric. and Biol. Chem. (Japan) 1976 40 1971; W. L. Roelofs J. P. Kochansky R. T. CardC G. G. Kennedy C. A. Henrick J. N. Labovitz and V. L. Corbin Life Sci. 1975 17 699. R. L. Petty M. Boppre D. Schneider and J. Meinwald Experientia 1977 33 1324. 367 R. Baker and D. A. Evans Table Some sex pheromone attractants of Lepidoptera species Parent Terminal chain functional length group Unsaturation Cl2 c13 c14 Acetate Acetate Alcohol (21-9(E,E)- 8,lO (E,Zb4,7(E,Z,Z)-4,7,10 - (€)-11 Acetate (Z)- 1 1 (2,E)-9,12 - (E)-9 (21-9(E)-1 1 c16 Aldehyde Alcohol Acetate (Z)- 1 1 (E,E)-9,11 (Z,E)-9,12 (21-7(E)- 1 1 (2)-11 (2)-11 (Z1-9(E)- 1 1 (2)-1 1 cl8 Aldehyde Aldehyde (2)-1 1 (E,Z)-6,11 (E,Z)-6,11 (2)-13 Species A Eupoecilia ambiguella ; B Rhyacionia rigidana ;C Phthorimaea operculella ; D Platynota PaVedanu; E Archips rosana; F Ephestia cautella; G Ostrinia nubilalis (Iowa); H Pandemis limitata; I Pandemis pyrusana ;J Naranga aenescens; K Epiphyas postvittana ;L,Archippus breviplicanus; M Prays citri; N Choristoneura fumiferana ;0,Scotogramma trifolii; P,Brachmia macroscopa ;Q Sesamia inferens ; R Antheraea polyphemus; S Chilo suppressalis; T,Heliothis armigera.a H. Am S. Rauscher H. R. Buser and W. L. Roelofs 2.Naturforsch. 1976,31c 9; A. S. Hill C. W. Berisford U. E. Brady and W. L. Roelofs Environ. Entomol.1976,5,959; C. J. Persoons S. Voerman P. E. J. Verwiel F. J. Ritter W. J. Nooijen and A. K. Minks Entomol. Exp. Appl. 1976,20 289; see also R. Yamaoka H. Fukami and S. Ishii Agric. and Biol. Chem. (Japan) 1976,40 1971 and W. L. Roelofs J. P. Kochansky R. T. Cardi G. G. Kennedy C. A. Henrick J. N. Labovitz and V. L. Corbin Life Sci. 1975,17,699; A. S. Hill R. T. CardC W. M. Bode and W. L. Roelofs J. Chem. Ecol. 1977,3,369;'W. L. Roelofs A. S. Hill A. Cardi R. T. Cardt J. Vakenti and H. Madsen Environ. Entomol. 1976,5,362; J. S. Read and C. P.Haines J. Stored Product Res. 1976. 12 49; see also ibid. p. 55; J. A. Klun and G. A. Junk J. Chem. Ecol. 1977 3 447; W. L. Roelofs A. Cardt A. S. Hill and R. T. Cardt Environ. Entomol. 1976 5 649; W.L. Roelofs R. F. Lagier and S. C. Hoyt ibid. 1977 6 353; T. Ando K. Kishino S. Tatsuki H. Nakajima S. Yoshida and N. Takahashi Agric. and Biol. Chem. (Japan) 1977,41 1819; 'R. J. Bartell and L. A. Lawrence Physiol. Entomol. 1977 2 89; H. Sugie K. Yaginuma and Y. Tamaki Appl. Entomol. Zool. 1977 12 69; B. F. Nesbitt P. S. Beevor D. R. Hall R. Lester M. Sternlicht and S. Goldenberg Insect Biochem. 1977,7 355; C. J. Sanders and J. Weatherston Canad. Entomol. 1976,108 1285; see also Compt. rend. 1975,281 D 1111; E. W. Underhill W. F. Steck and M. D. Chisholm Environ. Entomol. 1976 5,307; 'C. Hirano H. Muramoto and M. Horiike Naturwiss. 1976,63,439; B. F. Nesbitt P.S. Beevor D. R. Hall R. Lester and V. A. Dyck Insect Biochem. 1976 6 105; J. Kochansky J. Tette E.F. Taschenberg K. E. Kaissling and W. L. Roelofs J. Insect Physiol. 1975 21 1977; 'B. F. Nesbitt P. S. Beevor D. R. Hall R. Lester and V. A. Dyck J. Insect Physiol. 1975 21 1883; K. Ohta S. Tatsuki K. Uchiumi M. Kurihara and J. Fukami Agric. and Biol. Chem. (Japan) 1976 40 1897; P. Piccardi A. Capizza G. Cassani P. Spinelli E. Arsura and P.Massardo J. Insect Physiol. 1977 23 1443. Biological Chemistry-Part (ii) Insect Chemistry 369 plants are postulated to contribute to the unpalatability of these butterflies to potential predators.' Specialized organs on the hindwings of male Ithomiinae butterflies secrete the lactone (6)which is structually related to the esterifying acids of pyrollizidine alkaloids.8 0 R (1) a; R = n-CgHl9 b; R = n-C8HI7 0 I The differences of sex attractant responses of Grapholitha molesta male moths to subtle changes in component ratio of a binary pheromone have been attributed to a normal distribution of responses about an optimum mixture rather than to genetic variation within a single species.' Furthermore two Archips sibling species main- tain reproductive isolation by employing different blends of the same chemicals as sex pheromones.lo The effects of enantiomeric'l and geometric12 composition on response have also been investigated. Attractants have been discovered for many economically important moth species as a result of screening programrne~.'~ The Eastern Tent Caterpillar Malacosoma americanum forages by preception of chemicals present in trails of silk leading from the communal tent to distant food sources.l4 Many male Noctuid moths possess eversible glandular structures and the genital scent brushes of several species release oxygenated aromatic compounds (e.g. 2-phenylethanol) which elicit sexual behaviour in the females of those spe- cie~.~~ ' J. A. Edgar P. A. Cockrum and J. L. Frahn Experientia 1976,32 1535. * J. A. Edgar C. C. J. Culvenor andT. E. Pliske J. Chem. Ecol. 1976,2 263. ' R. T. Card& T. C. Baker and W. L. Roelofs Experientia 1976,32 1406. lo R. T. Card& A. M. CardC A. S. Hill and W. L. Roelofs J. Chem. Ecol. 1977,3 71. 11 D. Klimetzek G. Loskant J. P. Vite and K. Mori Naturwiss. 1976 63 581. 12 R. T. Card& and W. L. Roelofs J. Chem. Ecol. 1977,3 143. 13 E.W. Underhill M. D. Chisholm and W. Steck Enuiron. Entomol. 1977 6 333; K. Yaginuma M. Kurnakura Y. Tamaki T. Yushima and J. H. Tumlinson Appl. Entomol. Zool. 1976 11,266; L. I. Butler J. E. Halfhill L. M. McDonough and B. A. Butt J. Chem. Ecol. 1977,3,65;W. Steck E. W. Underhill B. K. Bailey and M. D. Chisholm Enuiron. Entomol. 1977 6 270; V. E. Adler M. Jacobson J. F. Edrniston and M. H. Fleming J. Econ. Entomol. 1976 69 706; A. K. Minks S. Voerman and M. Van de Vrie Entomol. Exp. Appl. 1976 19 301; W. F. Steck B. K. Bailey E. W. Underhill and M. D. Chisholm Enuiron. Entomol. 1976,5,523; W. L. Roelofs W. H. Reissig and R. W. Weires ibid. 1977 6 373; R. E. Doolittle W. L. Roelofs J. D. Solomon R. T. CardC and M. Beroza J. Chem. Ecol. 1976,2 399. 14 T.D. Fitzgerald and E. M. Gallagher J. Chem. Ecol. 1976 2 187. 15 M. Jacobson V. E. Adler A. N. Kishaba and E. Priesner Experientia 1976,32,964;H. J. Bestrnann 0.Vostrowsky and H. Platz ibid. 1977 33 874. R. Baker and D. A. Evans In the Coleoptera alcohols and hydrocarbons are employed by female boll weevils (Anthonomus grandi:) as sex attractants for males.16 Further investigations of several species of Trogoderma Dermestid beetles have shown the importance of (7a) and (7b) in addition to1s:ompounds reported earlier in mating behavi~ur,~'*'' and an informative summary of the chemical basis for interspecific and intraspecific responses has been presented." A major sex-attracting component produced by virgin female Attagenus elungatus beetles is reported as (8),20whereas the female Japanese Beetle Pupillia japonica employs (9) as a sex pheromone.21 It is reported in this context that racemic (9)is completely inactive whereas the (S)-enantiomer is inhibitory.Aromatic derivatives including (1 0) are male-specific natural products in the bug Leptoglossus phyllopus.22 CHO (7a) (7b has E-geometry) 0LJ...J8"" H Me0 QOMe OH (9) (10) Pest species of flies have again attracted considerable attention. Females of the stable fly species Stomoxys calcitrans produce a mating stimulant consisting of methyl-branched and 1,5-dimethyl-branched hydrocarbons of which 1S-methyl-tritriacontane and 15,19-dimethyltritriacontaneare most active in behavioural bioa~says.~~ In this context it is interesting to note that (2,Z)-pentacosa- 1,7,13- triene is a major cuticular wax component for males of this species but is absent in The mating-stimulant pheromones and cuticular lipid constituents of the Little House Fly Fannia canicularis have been investigated.Newly emerged l6 G. H. McKibben P. A. Hedin W. L. McGovern N. M. Wilson and E. B. Mitchell J. Chem. Ecol. 1977 3 331. l7 J. H. Cross R. C. Byler R. F. Cassidy jun. R. M. Silverstein R. E. Greenblatt W. E. Burkholder A. R. Levinson and H. 2.Levinson J. Chem. Ecol. 1976 2,457. R. E. Greenblatt W. E. Burkholder J. H. Cross R. C. Byler and R. M. Silverstein J. Chem. Ecol. 1976; 2 285; J. H. Cross R. C. Byler R. E. Greenblatt J. E. Gorman and W. E. Burkholder ibid. 1977 3 115. f9 R. E. Greenblatt W.E. Burkholder J. H. Cross R. F. Cassidy jun. R. M. Silverstein A. R. Levinson and H. Z. Levinson J. Chem. Ecol. 1977,3 337. 2o H. Fukui F. Matsumura A. V. Barak and W. E. Burkholder J. Chem. Ecol. 1977 3 539. *' J. H. Tumlinson M. G. Klein R. E. Doolittle T. L. Ladd and A. T. Proveaux Science 1977 197 789. 22 J. R. Aldrich M. S. Blum S. S. Duffey and H. M. Fales J. Insect Physiol. 1976 22 1201. 23 P. E. Sonnet E. C. Uebel R. L. Harris and R. W. Miller J. Chem. Ecol. 1977 3 245. 24 P. E. Sonnet E. C. Uebel and R. W. Miller J. Chem. Ecol. 1977,3,251. Biological Chemistry-Part (ii) Insect Chemistry 371 adults of both sexes have identical lipid constituents but considerable differences are apparent after five days. (2)-9-Pentacosene constitutes 66% of female lipids compared to 1% in males and this component is suggested as a sex pheromone.” The long-running saga of the sex pheromone of the American Cockroach Periplaneta americana has been advanced by the proposal of (11) as a tentative structure.26 Interestingly the structurally related germacrene-D (12) has been found to be a phytochemical sex-stimulant for this specie^.'^ (1 1) (12) The chemistry of the metasternal gland of the Eucalypt Longhorn Phorocantha synonoma has been studied and the existence of several lactones [e.g.(13)] has (13) I/ been demonstrated.28 A second component of the sex pheromone of the German Cockroach Blattella germanica has been shown to be (14).29 3,7-Dimethyl-HO(CH2)17CH(CH&CHCOMe I I Me Me (14) pentadecan-2-01 (15) plays a key role in the sexual behaviour of three sawfly species and inter-species specificity is based upon pheromone blends of (15) and the corresponding acetate and propionate esters.30 (15) ’ 25 E.C. Uebel P. E. Sonnet R. E. Menzer R. W. Miller and W. R. Lusby J. Chem. Ecol. 1977,3,269. 26 C. J. Persoons P. E. J. Verwiel F. J. Ritter E. Talrnan P. J. F. Nooijen and W. J. Nooijen Tetrahedron Letters 1976 2055. ’’C.Kitamura S. Takahashi S. Tahara and J. Mizutani Agric. and Biol. Chem. (Japan) 1976 40 1965; C. Nishino T. R. Tobin and W. S. Bowers J. Insect Physiol. 1977,23,415. B. P. Moore and W. V. Brown Austral. J. Chem. 1976,29 1365. 29 R. Nishida T. Sato Y. Kuwahara H. Fukami and S. Ishii J. Chem. Ecol. 1976 2 449.30 D. M. Jewett F. Matsumura and H. C. Coppel Science 1976,192 51. R. Baker and D. A. Evans 3 Aggregation Pheromones and Population Attractants This complex area of interplay between host phytochemicals and pheromones has continued to attract considerable The aggregation pheromone complex reported earlier’ for the European Elm Beetle Scolytus multistriatus is also associated with the Larger European Elm Beetle S. sc~lytus.~~ The availability by synthesis (Section 13) of enantiomers and isomers of bark-beetle pheromones has enabled testing of response ~pecificity.~~ The dioxaspirononane (16) has been (16) reported as an aggregation pheromone of Pityogenes chalcographus a pest of Norway spruce.35 4 Pheromones of Social Insects and Related Species The complexity of chemosensory communication is amply illustrated by detailed investigations of the behaviour of social insects.36 Chemical and ethological studies of the Dufour’s gland secretion of the ant Myrmica rubra have related specific behavioural responses to individual components of the ~ecretion.~’ The male mandibular gland secretion of the ant Camponotus clavithorax is a complex mixture containing (17),38 whereas the volatiles associated with two Formica species are largely monoterpenoids together with methyl 3-isopropylpentanoate (1 8).39 Alarm pheromone components have been reported for several ant species,4o including (19) for eight Formica specie^,^' and (20) for Hypoponera opacior and Ponera pennsyl~anica.~~ The lactone (21) occurs together with terpenoids in the mandi- bular gland secretion of carpenter bees.43 A number of terpenoid alcohols and esters have been implicated in flight-marking in bumblebee^,^^ and neral and 31 J.P. Vite and W. Francke Nuturwiss. 1976 63 550. 32 C. M. Harring J. P. Vite and P. R. Hughes Nuturwiss. 1975 62 488; J. A. A. Renwick G. B. Pitman and J. P. Vite ibid. 1976,63 198; J. A. A. Renwick J. P. Vite and R. F. Billings ibid. 1977 64 226; M. C. Birch P. E. Tilden D. L. Wood L. E. Browne J. C. Young and R. M. Silverstein J. Insect Physiol. 1977 23 1349. 33 M. M. Blight F. A. Mellon L. J. Wadhams and M. J. Wenham Experientiu 1977,33 845. 34 D. L. Wood L. E. Browne B. Ewing K. Lindahl W. D. Bedard P. E. Tilden K. Mori G. B.Pitman and P. R. Hughes Science 1976,192 896; J. H. Borden L. Chong J. A. McLean K. N. Slessor and K. Mori ibid. p. 894; G. N. Lanier W. E. Gore G. T. Pearce J. W. Peacock and R. M. Silverstein J. Chem. Ecol. 1977.3 1. 35 W. Francke V. Heeman B. Gerken J. A. A. Renwick and J. P. Vite Nuturwiss. 1977,64,590. 36 Proceedings of the 8th International Conference of the International Union for the Study of Social Insects Wageningen Netherlands 1977; published by the Centre for Agricultural Publishing and Documentation Wageningen. 37 M. C. Cammaerts-Tricot E. D. Morgan R. C. Tyler and J. C. Braekman J. Insect Physiol. 1976 22 927; see also ibid. 1977 23 511. 38 H. A. Lloyd M. S. Blum and R. M. Duffield Insect Biochem. 1975 5,489. 39 M. Buehring W.Francke and V. Heeman 2.Nuturforsch. 1976,31c 11. 40 J. Lofquist J. Insect Physiol. 1976 22 1331; N. Hayashi and H. Komae Experientiu 1977 33,424. 41 R. M. Duffield J. M. Brand and M. S. Blum Ann. Entomol. SOC.Amer. 1977 70 309. 42 R. M. Duffield M. S. Blum and J. W. Wheeler Comp. Biochem. Physiol. (B) 1976 54,439. 43 J. W. Wheeler S. L. Evans M. S. Blum H. H. V. Velthuis and J. M. F. de Camargo Tetrahedron Letters 1976 4029; see also Ann. Entomol. SOC. Amer. 1977 70,635. 44 B. G. Svensson and G. Bergstrom Insectes Sociuux 1977,24 213. Biological Chemistry -Part (ii) Insect Chemistry geranial have been suggested as components of the sex pheromone of the parasitic wasp Itoplectis conq~isitor.~~ Faranal (22) reminiscent of a juvenoid is proposed as a trail pheromone of Pharaoh’s Ant Monomorium pharaoni~.~~ The configuration of the two adjacent methyl groups was established to be as shown (or its antipode) by comparison of the ozonolysis product of faranal with that of trans-3,4-dimethylcyclohexene.C0,Me 5 Alarm Behaviour in Aphids Alarm behaviour in aphid species has been extensively studied. When attacked by predators aphids of the Therioaphis genus secrete droplets containing (-)-germacrene-A (23).47 Sesquiterpenoid hydrocarbons such as (E)-P-farnesene (24) function as alarm pheromones in aphids and norfarnesenes also elicit this response.48 It is considered unlikely that such compounds are sufficiently stable for field use in control methods. 6 Defence Secretions Defence secretions are generally produced by insects in much larger quantities than sex pheromones.This consideration together with the impetus provided by the possibility of uncovering novel insecticides accounts for the relatively large number of intricate and diverse structures elucidated in this area. An interesting review on arthropod protective agents has appeared.49 4s D. C. Robacker and L. B. Hendry J. Chem. Ecol. 1977 3 563. 46 F. J. Ritter I. E. M. Bruggemann-Rotgans P. E. J. Verwiel C. J. Persoons and E. Talman Tetrahedron Letters 1977 2617. 47 W. S. Bowers C. Nishino M. E. Montgomery L. R. Nault and M. W. Nielson Science 1977 196 4290; see also J. Chem. Ecol. 1977.3 349. 48 C. Nishino W. S. Bowers M. E. Montgomery and L. R. Nault Agric.and Biol. Chem. (Japan) 1976 40 2303; see also J. Insect Physiol. 1977 23 697; Appl. Entomol. Zool. 1976 11,340. 49 H. Schildknecht Angew. Chem. Internat. Edn. 1976,15 214. R. Baker and D. A. Evans The defensive substances of the Opilionids Leiobunum uentricosum and Hadro -bunus maculosus are reported as (25a) and (25b) in addition to 4-methylheptan-3- one.” In ants components of defence secretions range from simple aliphatic compounds in Formica species 51 to iridoid monoterpenoid~~~ such as iridomyr- mecin (26) and dolichodial (27).53 The powerful alkaloidal venoms of fire ants have Rd.Jy 0-FCHO EO CHO (25) a; R=Me HO b; R=Et (26) (27) been inter-related chemotaxonomically,54 and a South African species (Solenopsis punctaticeps) has been shown to contain a novel series of 2,5-dialkyl-pyrrolidines and -pyrrolines (28a-d) and (29a b and c).” Ladybugs indigenous to Canada R’LA N R2 H (28) a; R’ = C2,R2= C5 (29) a; R’ = C4,R2 = C5 b; R’ = Cg R2 = C2 b; R’ = Cz R2= C7 c; R’ = Cz R2= C7 C;R’= c4,R~= C d; R’ = C7 R2= C2 Numbers refer to length of n-alkyl chain (Hippodamia caseyi) have been found to utilize a series of defensive alkaloids [e.g.(30) (3l)],closely related to structures discovered earlier.56 Quinone and hydro- carbon defence chemicals from five genera of bombardier beetles have been (30) (31) listed,57 and the cyclopentanoid monoterpenoids chrysomelidial (32) and plagiolactone (33) are components of the larval defensive secretion of the chry- T.H. Jones W. E. Conner A. F. Kluge T. Eisner and J. Meinwald Experientia 1976 32 1234. J. Lofquist Oikos 1977 28 137. ’’ J. W. Wheeler T. Olagbemiro A. Nash and M. S. Blum J. Chem. Ecol. 1977,3 241. 53 G. W. K. Cavill E. Houghton F. J. McDonald and P. J. Williams Insect Biochern. 1976,6 483. s4 J. G. MacConnell M. S. Blum W. F. Buren R. N. Williams and H. M. Fales Toxicon 1976,14 69. ” D. J. Pedder H. M. Fales T. Jaouni M. S. Blum J. G. MacConnell and R. M. Crewe Tetrahedron 1976,32,2275. 56 W. A. Ayer M. J. Bennett L. M. Browne and J. T. Purdham Canad. J. Chem. 1976,54 1807. ” T. Eisner T. H. Jones D. J. Aneshansley W. R. Tschinkel R. E. Silberglied and J. Meinwald J. Insect. Physiol. 1977 23. 1383. Biological Chemistry -Part (ii) Insect Chemistry somelid beetle Plagiodera ver~icolora.~~ The water beetle Platambus maculatus uses platambin (34) in a defensive a full report of the defensive behaviour of Stenus comma has also appeared.60 (E)-Oct-2-enal and (E)-hex-2-enal are present in the defensive scent of the Black Stink Roach a New Zealand cockroach sDecies.6 yLoCHO %o 0 * i>H (32) (33) (S s-?) (34) It has long been recognized that the defensive secretions of many termite species contain complex oxygenated diterpenoids.In particular the sprays ejected at attackers by the nozzle-like heads of nasute soldiers frequently contain such substances. Several of these structures have been elucidated by X-ray methods in conjunction with microchemical studies. The soldier caste of the termite Tri-nervitermes gratiosus contains in addition to five monoterpenoids,62 an intriguing series of novel diterpenoids [e.g.(35)] based on the ‘trinervitene’ ~keleton.~~ The soldiers of Nasutitermes kempae the structurally related isomers of (36).The frontal gland defence secretion of Macrotermes subhyalinus contains a mixture of alkanes and alkene~,~~ whereas Schedorhinotermes species produce long-chain enones [e.g. (37)] and ketones.66 (35) (36) (37) 7 Host Food Host Prey and Oviposition Attractants On the whole the investigations of chemical signs which are used by phytophagous insects in host selection have advanced surprisingly slowly over the past few years. J. Meinwald T. H. Jones T. Eisner and K. Hicks Proc. Nut. Acad. Sci.U.S.A. 1977 74 2189. 59 H. Schildknecht H. Holtkotte and D. Krauss Ann. Chem. 1975 1850. 6o H. Schildknecht D. Burger D. Krauss and J. Connert J. Gehlhaus and H. Essenbreis J. Chem. Ecol. 1976 2 1. M. H. Benn R. F.N. Hutchins and R. Folwell J. Insect Physiol. 1977,23 1281. 62 G. D. Prestwich Insect Biochem. 1977,7 91. 63 G. D. Prestwich S. P. Tanis J. P. Springer and J. Clardy J. Amer. Chem. Soc. 1976 98 6061; see also ibid. p. 6062. 64 G. D. Prestwich B. A. Solheim J. Clardy F. G. Pilkiewicz Z. Miura S. P. Tanis and K. Nakanishi 1.Amer. Chem. SOC.,1977,99,8082. 65 G. I).Prestwich B. A. Bierl E. D. Devilbiss and M F. B. Chaudhury J. Chem. Ecol. 1977 3,579. 66 G. D. Prestwich M. Kaib W. F. Wood and J. Meinwald Tefruhedron Letters 1975 4701. R.Baker and D. A. Evans It has been reported that the attraction of adult Cabbage Maggots Hylemya brassicae is mediated by ally1 isothiocyanate whereas oviposition is induced by plant glucosinolates.67 Dipropyl disulphide released by leek leaves stimulates significant egg-laying behaviour in the leek moth Acrolepiopsis assectella.68 A detailed study of Indian Calamus Root oil has unearthed a number of compounds which are attractants of fruit-fly species [e.g.acroagermacrone (38)].69 (38) Chemical cues used by parasitoids of insects have received considerable attention (e.g. ref. 70). The parasitoid Biosteres longicaudatus locates its fruit-fly host by perception of fermentation products of rotting Kairomones used by parasi- toids have been found in food plants of the host insects and it has been proposed on the basis of radiotracer evidence that such kairomones are ingested concen- trated and then released unaltered by the A case of aggressive chemical mimicry has been reported for a female Masto-phora spider which attracts prey with a volatile substance which apparently mimics the female-produced sex attractant of the Fall Armyworm Spodoptera frugiperda.This hypothesis is corroborated by the observation that only males of the latter species are trapped and that these are attracted from downwind both points being characteristic of mating beha~iour.~~ 8 Antifeedants and Repellants The interactions between plants and insects have been reviewed.74 There have been numerous reports of antifeedant and insecticidal activity of plant constituents but coverage here is limited to compounds which have pronounced effects suppor- ted by bioassay results.Quinones [e.g. (39)] are constituents of pest-resistant strains of cotton and are associated with insecticidal and larval growth-inhibitory 67 K. S. S. Nair and F. L. McEwen Canad. Entomol. 1976 108 1021. J. Boscher Compt. rend. 1977,284 D 635. " M.Jacobson I. Keiser D. Miyashita and E. J. Harris Lloydia 1976 39 412. 70 R. D. Henson S. B. Vinson and C. S. Barfield J. Chem. Ecol. 1977,3 151. 71 P.D. Greany J. H. Tumlinson D. L. Chambers and G. M. Bousch J. Chem. Ecol. 1977,3 189. 72 L. B. Hendry J. K. Wichmann D. M. Hindenlang K. M. Weaver and S. H. Korzeniowski J. Chem. Ecol. 1976 2 271. 73 W. G.Eberhard Science 1977,198 1173. 74 H. Z. Levinson Experientia 1976 32 408. Biological Chemistry -Part (ii) Insect Chemistry proper tie^.^^ Four dialdehydes [e.g.muzigadial (40)]have been reported as potent armyworm anti feed ant^.^^ Nic-1 (41) is one of a number of oxygenated steroids from the plant Nicandra physaloides which has an inhibitory effect on larval feeding,77 and harrisonin (42) is reported to have similar proper tie^.^^ Diter-CHO ] \ 0 'OH HI / HO "0 (41) Denoids have also been implicatec in host-p.mt resistance and antifeedant beha~iour.~~ Oviposition deterrents" and inhibitors" represent relatively new areas of study and it is felt that such responses might be important in developing novel control methods.9 Biosynthesis and Biotransformation A major point of controversy has centred on the possibility that pheromones of the Lepidoptera may be derived from the diet.82 Subsequent examination of this postulate established that the 67 :33 (E)-ll-:(2)-11-tetradecenyl acetate pheromone composition of the Oak Leaf Roller did not vary irrespective of whether the insect had been reared on oak leaves or an artificial diet thus sugges- ting specific biosynthe~is.~~ Indeed a re-examination of previous results now accords to the latter view.84 The biosynthesis of the hairpencil pheromone 7s R. D. Stipanovic A. A. Bell D. H. O'Brien and M. J. Lukefahr Tetrahedron Letfers 1977 567; J. R. Gray T. J. Mabry A. A. Bell R. D. Stipanovic and M. J. Lukefahr J.C.S. Chem.Comm.,1976 109. 76 I. Kubo 2.Miura M. J. Pettei Y.W. Lee F. Pilkiewicz and K. Nakanishi Tetrahedron Letters 1977 4553; I. Kubo Y. W. Lee M. J. Pettei F. Pilkiewicz and K. Nakanishi J.C.S. Chem. Comm. 1976 1013. 77 M.J. Begley L. Crombie P.J. Ham and D. A. Whiting J.C.S. Perkin I 1976 296 304. 78 I. Kubo S. P. Tanis Y. W. Lee I. Miura K. Nakanishi and A. Chapya Heterocycles 1976,5,485. 79 I. Kubo I. Miura K. Nakanishi T. Kamikawa T. Isobe and T. Kubota J.C.S. Chem. Comm. 1977 555; A. C. Waiss jun. B. G. Chan C. A. Elliger V. H. Garrett E. C. Carlson and B. Beard Nuturwiss. 1977,64 341; T. Ikeda F. Matsumura and D. M. Benjamin Science 1977 197 497. J. Hurter B. Katsoyannos E. F. Boller and P. Wirz 2.angew. Entomol. 1976,80 50. H. M. Flint R. L. Smith J. G.Pomonis D. E. Forey and B. R. Horn J. Econ. Entomol. 1977,70,547. 82 L. B. Hendry Science 1976 192,143; ibid. 1975 188,59. 83 J. R. Miller T. C. Baker R. T. Cardt and W. L. Roelofs Science 1976,192 140. 84 D. M. Hindenlang and J. K. Wichmann Science 1977,195 86. R. Baker and D. A. Evans secretion of 2-phenylethanol in males of Mamestra configurata has been studied both in uivo and in vitro with crude homogenates and a detailed pathway from phenylalanine has been mapped out. It has been noted that this pheromone is stored in Stobbe's gland as 2-phenethyl-P -glycoside which is hydrolysed on requirement by enzymes contained in hairpencil cap cells.85 Oleic acid appears to be the biosynthetic precursor of n-nonanal a pheromone of the Greater Waxmoth Galleria melonella.86 The production of pheromones in bark beetles by allylic oxidation of un-saturated terpenoid hydrocarbons has attracted much attention.87 The intriguing problem of cantharadin (43) biosynthesis in male Spanish flies has been studied by feeding and successful incorporation of radiolabelled mevalonate farnesol and methyl farnesoate.88 It is interesting to note that the female is unable to produce this defensive material but acquires it by transfer from the male during copulation. 10 Perception of Stimuli The availability of synthetic samples of enantiomerically pure pheromones has much aided studies of olfactory specificity (e.g.refs. 89 and 90). The monitoring of olfactory responses by electroantennography (EAG) and single-cell recording has been applied to investigations of many types of stimulus e.g.host-plant attrac- tant~,~~ cockroach sex attractant^,'^ and Lepidopterous pheromone^.'^ A good correlation between the EAG method and behavioural bioassays was obtained for the repellancy towards Reticulitermes termites of series of quinones and terpenoids of plant origin.94 The roles of thiol and disulphide groups in nerve receptors for u5 J. Weatherston and J. E. Percy Insect Biochem. 1976 6,413; ibid. 1975 5 737. u6 S. P. Schmidt and R. E. Monroe Insect Biochem. 1976,6 377. 87 J. A. A. Renwick P. R. Hughes G. B. Pitman and J. P. Vite J. InsectPhysiol. 1976,22,725;J. A. A. Renwick P. R. Hughes and I. S. Krull Science 1976 191 199; J. M. Brand J. W. Bracke L. N. Britton A.J. Markovetz and S. J. Barras J. Chem. Ecol. 1976 2 195; P. A. Hedin ibid. 1977 3 279. J. R. Sierra W. D. Woggon and H. Schmid Experientia 1976 32 142; Helv. Chim. Acta 1977 60 2288. u9 J. P. Vite D. Klimetzek G. Loskant R. Hedden and K. Mori Naturwiss. 1976,63 582. M. Yamada T. Saito K. Katagiri S. Iwaki and S. Marumo J. Insect Physiol. 1976 22 755. " R. F. Simpson and R. M. McQuilkin Entomol. Exp. Appl. 1976,19 205. 92 H. Washio and C. Nichino J. Insect Physiol. 1976,22 735; C. Nishino H. Washio K. Tsuzuki W. S. Bowers and T. R. Tobin Agric. and Biol. Chem. (Japan) 1977,41,405. 93 T. C. Baker and W. L. Roelofs J. Insect Physiol. 1976 22 1357; Y. Aihara and T. Shibuya ibid. 1977 23 779; T. t.Payne and W. E. Finn ibid. p. 879. 94 M. A. Floyd D.A. Evans and P. E. Howse J. Insect Physiol. 1976 22 697. Biological Chemistry-Part (ii) Insect Chemistry 379 quinone repellants in the American Cockroach have been chemically investi- gated.'' 11 Techniques of Microscale Structure Elucidation The past two years have seen further improvements in the power and sensitivity of both separative and spectroscopic technique^.^^ Attention has been paid to efficient methods of selective extraction of behaviourally active insect chemicals e.g. collection on Porapak Q of volatiles being produced by living insects." This method has particular relevance to cases where pheromones are stored as pre- cursors prior to release. Another useful technique consists of milking pheromone- producing glands with micro-capillaries followed by direct 'solid sample' injection on to a gas chromatograph (g.~.).~' A number of adaptations of gas chromato- graphy to insect chemistry have been reported,98 the most spectacular of which is the monitoring of the response potentials of excised antennae placed post-column in an emergent g.c.gas stream as a selective pheromone dete~tor.~' An efficient splitter-trapping system for micropreparative g.c. has been described,"' and the use of g.c. combined with 13Cn.m.r. spectroscopy has been reported for the separation and determination of purity of geometric isomers of dienes.lo' The enantiomeric composition of several insect pheromone alcohols and acetals has been determined by microscale n.m.r. methods using chiral shift reagents and by formation of diastereisomeric Mosher derivatives."* 12 Behaviour-modifying Chemicals in Pest Control The largest increase in activity in the area of chemical ecology has been observed in the field evaluation of behaviour-modifying chemicals in potential pest control programmes particularly in terms of population survey behaviour disruption and trap baiting.'03 The importance of such factors as enantiomeric puritylo4 and the correct design of traps"' has been emphasized.As expected reports range from significant successes (e.g. ref. 106) to disappointment (e.g.ref. 107). In other cases methods based on chemical ecology offer a comparable alternative to conventional methods.lo8 95 D. M. Norris J. M. Rozental and G. Samberg Cornp. Biochem. Physiof.(C),1977 57 55. 96 J. H. Tumlinson and R. R. Heath J. Chem. Ecol. 1976 2 87. 97 E. D. Morgan and R. C. Tyler J. Chromatog. 1977,134 174. 98 E. Talman P. E. J. Verwiel and A. C. Lakwijk Adu. Mass. Spectrom. Biochem. Med. 1977,2,215; L. M. MacDonald and J. Weatherston J. Chromatog. 1976 118 195. 99 H. Am E. Staedler and S. Rauscher 2.Naturforsch. 1975 30c 11. loo R. Baker J. W. S. Bradshaw D. A. Evans M. D. Higgs and L. J. Wadhams J. Chromatog. Sci. 1976 14,425. H. Disselkoetter K. Eiter W. Karl and D. Wendisch Tetrahedron 1976 32 1591. '02 T. E. Stewart E. L. Plummer L. L. McCandless jun. J. R. West and R. M. Silverstein J. Chem. Ecol. 1977,3,27;E. L. Plummer T. E. Stewart K. Byrne G. T. Pearce and R. M. Silverstein ibid. 1976,2 307. P. A. Hedin Cherntech.1976,6 444. lo4 J. R. Miller K. Mori and W. L. Roelofs J. Znsect Physiof. 1977 23 1447. lo' E. D. M. Macauley and T. Lewis Ecol. Entomol. 1977 2 279. lo6 H. Am B. Deliey M. Baggiolini and P. J. Charmillot Enromol. Exp. Appf. 1976 19 139. Io7 M. D. Proverbs D. M. Logan and J. R.Newton Canad. Entomol. 1975,107 1265. L. K. Gaston R. S. Kaae H. H. Shorey and D. Sellers Science 1977 1% 904; P. H. Westigard and K. L. Graves Canad. Entomol. 1976,108 379. R. Baker and D. A. Evans 13 Synthetic Studies Valuable reviews on the methodology of pheromone ~ynthesis,'~'-~ '' the synthesis of optically active pheromones,' l2 and the synthesis of insect sex attractants on solid phase^^'^?''^ have appeared. Acyclic derivatives.-Two methods which have general applicability have been used in the synthesis of the queen substance 9-oxo-(E)-dec-2-enoic acid.The first involves the sulphenylation and dehydrosulphenylation of esters or ketones,' whereas the key step in the second is an oxidative cleavage which is accompanied by rearrangement of a 2,2-dithiocycloalkan- 1-01(44)(Scheme l).' l6 Conversion of (45) into the queen substance was then achieved by addition of methylmagnesium OHC / C0,Me Reagents i Pb(OAc),; ii MeOH-J2; iii NaI04; iv pyrolysis Scheme 1 chloride followed by Jones oxidation. The queen substance has also been synthesized by a route beginning with reaction of butadiene with diethyl malonate catalysed by palladium acetate and triphenylphosphine.'" In a similar way the same reaction but in the presence of carbon monoxide and t-butyl alcohol yields (46) (Scheme 2).Further carbonylation in presence of octacarbonyldicobalt yields +CO+BU'OH ii iii / CO2H -\ C0,Bu' ' H02C-(46) Reagents i Pd(OAc)z-PPh3; ii Co2(CO)S-MeOH; iii H30+ Scheme 2 log C. A. Henrick Tetrahedron 1977 33 1845. 'lo J. A. Katzenellenbogen Science 1976 194 139. 11' R. Rossi Synthesis 1977 817. '** K. Mori Gendai Kagaku,1976,61 51. 'I3 C. C. Leznoff and T. M. Fyles J.C.S. Chem. Comm. 1976,251. '14 T. M. Fyles C. C. Leznoff and J. Weatherston Canad. J. Chem. 1977,55 1143. '" B. M. Trost T. N. Salzmann and K. Hiroi J. Amer. Chem. SOC.,1976,98,4887. B. M. Trost and K. Hiroi J. Amer. Chem. SOC.1976,98,4313. ''' J. Tsuji K. Masaoka and T. Takahashi Tetrahedron Letters 1977 2267.Biological Chemistry -Part (ii) Insect Chemistry after hydrolysis dec-2-enedioic acid which is one of the components of royal jelly the sole nutrient of queen bee larvae.118 The absolute configuration of (-)-4-methylheptan-3-01 a pheromone of the Smaller European Elm Bark Beetle has been demonstrated to be (3S,4S)."' (R)-(+)-Citronellic acid was converted into a mixture of (3R,4R)-(+)-threo-and (3S,4R)-(+)-erythr0-4-methylheptan-3-01 which were separable by gas chromato- graphy. Manicone (E)-4,6-dimethyloct-4-en-3-one(48) the principal alarm pheromone of certain species of Manica ants has been prepared from a route (Scheme 3) in which the a@-unsaturated carbonyl moiety was introduced by reaction of a 4-chloro-2-pyrazolin-5-one(47) with aqueous sodium hydroxide.lzO Unfortunately Me0,C + LO+&Op+./ 0 HN-NH HN-N Reagents i NHzNHz-EtOH; ii C12-CH2Clz; iii NaOH; iv H30+; v SOC12-C,H,; vi EtzCd-benzene Scheme 3 the opening of the pyrazolinone gave a mixture of 2-and E-isomers and further separation was required.Optically active manicone has been prepared from the titanium tetrachloride-promoted reaction of the appropriately substituted vinyl trimethylsilyl ether and (+)-(2s)-or (-)-(2R)-2-methyIb~tyraldehyde.'~~ J. Tsuji and H. Yasuda J. Organometallic Chem. 1977,131 133. 119 K. Mori Tetrahedron 1977 33 289. I2O P. J. Kocienski J. M. Ansell and R. W. Ostrow I. Org. Chem. 1976 41 3625. K. Banno and T. Mukiayama Chem. Letters 1976 279. 382 R.Baker and D. A. Evans Further studies on the Ips bark beetle pheromones have appeared. Pyrolysis of the esters obtained from 3-methylbut-3-en-1-yl acetate and senecioic anhydride gave predominantly a ketone which on reduction yielded a racemic mixture of 2-methyl-6-methyleneocta-2,7-dien-4-ol, the main aggregation pheromone of Ips paraconfusus.‘22 A small amount of asymmetric induction was found in the forma- tion of 2-methyl-6-methyleneoct-7-en-4-01 and 2-methyl-6-methyleneocta-2,7-dien-4-01 by the coupling of Grignard reagents with the appropriate aldehydes in the presence of ( + )-(2S,3S)-NNN’N’-te trame thyl-2,3 -dime t hoxy bu tane- 1,4- diamine.123 Both enantiomers of the former compound have been synthesized from (S)-(+ )-leucine and its antipode.124 The (I?)-( -)-enantiomer of the dienol has been synthesized from (R)-( + )-glyceraldehyde acetonide obtainable from D-mannito1.12s The natural pheromone was demonstrated to have (S)-configura- tion. The sex pheromone of the female Red Bollworm Moth Diparopsis custanea (E)-dodeca-9,1l-dien-1-01 has been prepared from undec-10-en- 1-01.’~~ The route involved formation of (E)-1 1 -hydroxyundec-2-enal by allylic bromination followed by displacement and oxidation. Finally the synthesis was completed by reaction of methylenetriphenylphosphorane and the aldehyde. A four-step synthesis (Scheme 4) of the sex pheromone of the European Grape Vine Moth Lobesia botrana (E,Z)-dodeca-7,9-dien-l -yl acetate (50) has been reported via a functionalized organoborate.12’ Oct-7-ynyl acetate (49) was pre- pared from hept-1-yne via the acetylene ‘zipper’ reaction of oct-2-yn-1-01 with -/=-.... ,vi-viii Sia,B H H OAc kxi Sia = 3-methyl-2-butyl (50) OAc Reagents i KNH(CH2)3NH*; ii H20; iii Ac2O; iv SiazBH; v,A=-Li; vi 12; vii NaOAc; viii H202-NaOAc; ix Sia2BH; x AcOH; xi H202-NaOAc Scheme 4 lZ2 C. F. Garbers and F. Scott Tetrahedron Letters 1976 1625. S. Karlsen P. Froyen and L. Skattebol Actu Chem. Scand. 1976 B30,664. 124 K. Mori Tetrahedron 1976 32 1101. K. Mori Tetrahedron Letters 1976 1609. 126 J. H. Babler and M. J. Martin J. Org. Chem. 1977,42 1799. 12’ E. Negishi and A. Abramovitch Tetrahedron Letters 1977 411. Biological Chemistry-Part (ii) Insect Chemistry 383 potassium 3-aminopropylamide followed by acetylation.The subsequent reaction depended on the fact that triorganoboranes are much more reactive toward alkynyl-lithiums than the acetoxy-group. The pheromone (50) has also been synthesized by a route involving acid-catalysed ring opening of 1-cyclopropylpent-2-yn-1-01.'~~ Stereoselectivity of the reaction towards the conjugated (E)-enyne was obtained by complexion of the triple bond with octacarbonyldicobalts. (f)-Methyl n-tetradeca-trans-2,4,5-trienoate, produced by the male Dried Bean Beetle Acanthoscelides obtectus has been prepared in which the initial stage was a modified Claisen rearrangement on (51) to produce the allenic ester (52).129A (51) R=octyl (52) Beckmann fragmentation of the oxime (53)to the isomeric nitriles (54)provided the important stage in the synthesis of 3,7-dimethylpentadec-2-~1 acetate the sex pheromone of the Pine Sawfly Neodiprion lecontei (55).13* The preparation of v cR pyridine --+++ p-TsCI ~ CN OAc (53) R = heptyl (54) (55) erythro-3,7-dimethylpentadecan-2-acetate(58),the sex attractant of several species of pine sawflies has been prepared by a method which has more general appli~ability.'~' Beginning with cis-2,3-dimethylcyclohexanone,Baeyer-Villiger oxidation gave the lactone (56) which on reaction with octyllithium yielded the hydroxy-ketone (57).The acetate (58) was then obtained following a Wittig reaction reduction and acetylation. Further stereospecific syntheses have been reported by Bestmann and co-workers.The base sodium bis-trimethylsilylamide'32 has been employed to pro- duce (2)-olefin formation in the Wittig reaction and this procedure was used in the synthesis of (Z,Z)-7,11-and (Z,E)-7,1l-hexadecadienyl acetate the sex pheromone of Pectinophora g~ssypiella.'~~ The synthesis of a series of (E,Z)-conjugated dienes has also been A selective procedure for the general synthesis of conjugated (E,E)-and (E,Z)-dienes involving the reaction of (E)-128 D. Descoins D. Samain B. Lalanne-Cassou and M. Gallois Bull. Chem. SOC. France 1977 941. 129 P. J. Kocienski G. Cernigliaro and G. Felstein J.,Org. Chem. 1977 42 353. P. J. Kocienski and J. M. Ansell J. Org. Chem. 1977 42 1102. G. Magnusson Tetrahedron Letters 1977 2713. 13* H. J. Bestmann W.Stransky and 0.Vostrowsky Chem. Ber. 1976,109.1694. 133 H. J. Bestmann K. H. Koschatsky W. Stransky and 0.Vostrowsky Tetrahedron ktters 1976 353. 134 H. J. Bestmann 0.Vostrowsky H. Paulus W. Billman and W. Stransky Tetrahedron Letters 1977 121. R. Baker and D. A. Evans bii-v OAc Reagents i m-CIC6H4C03H-CH2C12; ii n-CsHl-/Li; iii Ph3P=CHz-HMPA-ether; iv H2-Pd/C- Et0.H; v AqO-pyridine Scheme 5 alkenylalanes (59) readily obtainable via hydroalumination of alkynes with alkenyl halides in the presence of palladium or nickel complexes has also been reported. 135 R' R' +X R1-Z HAIR2 PdLn RZ -R'>=(H /\ or H AIR2 NiLn (59) 1 R' R2 X A magnesium iodide rearrangement of a$-epoxysilane has been used to form p-ketosilanes (60).Subsequent treatment with methyl-lithium and sodium acetate in acetic acid gave (61) which was then transformed into 7-methyl-3-propyldodeca-2(2),6(Z)-dien-l-o1 previously obtained from the codling moth. 13' A synthesis (Scheme 7) of (62) the pheromone of the Parasitic Bean Weevil has involved the reaction of an allenic lithium cuprate with an acetylenic ester.13' Insoluble polymers have been used as supports in the synthesis of (2)-dodec-7- enyl (Z)-tetradec-g-enyl and (2)-tetradec- 11-enyl Stereoselective synthesis of the isomeric pentadeca-5,lO-dienals has been re~0rted.l~~ The (S)-enantiomers of (2)-and (E)-14-methylhexadec-8-en-1-01and the corresponding aldehydes which are sex pheromone components of dermestid beetles have been ~ynthesized.'~' In this work a new method for the stereospecific lithium aluminium hydride reduction of o-alkynols to the corresponding (E)-alkenols is described.14' S. Baba and E. Negishi J. Amer. Chem. SOC.,1976 98 6729. M. Obayashi K. Utirnoto and H. Nozaki Tetrahedron Letters 1977 1807. D. Michelot and G. Linstrumelle Tetrahedron Letters 1976 275. 13' C. C. Leznoff T. M. Fyles and J. Weatherston Canad. J. Chem. 1977 55,4135. G. Ohloff C. Vial F. Naf and M. Pawlak Helv. Chim. Acta 1977,60 1161. R.Rossi and A. Carpita Tetrahedron 1977 33 2447. 141 R.Rossi and A. Carpita Synthesis 1977 561. Biological Chemistry-Part (ii) Insect Chemistry H. SiMe SiMe I -=-SiMe -=-SiMe OH Reagents i MgI2-ether; ii MeLi; iii AcONa-AcOH Scheme 6 Reagents i BuLi; ii n-CgH17Br; iii BuLi; iv CuI; v r-C02Me Scheme 7 The sex pheromone of the Gypsy Moth (Z)-7,8-epoxy-2-rnethyloctadecane (65) has been synthesized by a Wittig reaction in presence of the base sodium bis- trimethyl~ilylarnide.'~~ The stereospecific reaction of (63) with the vinylsilane (64) has been used in the synthesis of (65)(Scheme 8).143 Both enantiomers of this I OAc li ii Reagents i H+; ii m-CIC6H4C03H Scheme 8 14' H.J. Bestrnann 0.Vostrowsky and W. Stransky Chem. Ber. 1976,109 3375. W. Mychajlowskij and T. H. Chan Tetrahedron Letters 1976 4439. R. Baker and D. A. Evans compound have been synthesized from the (2S,3S)-threo configuration of L-( +)-tartaric and the (7R,8S)-enantiomer has also been prepared from 1-menthyltoluene-p-sulphinate.145Further studies on the olefin metathesis reaction have appeared.The pheromones of the Housefly Face Fly and Gypsy Moth have been formed from suitable alkenes with homogeneous and heterogeneous cata- lyst~.~~~ A synthesis of muscalure (2)-9-tricosene in which the first step was reaction of an ester of oleic acid with pentylmagnesium bromide has been described.14’ Two interesting syntheses of (2)-6-heneicosen- 11-one (68) the sex pheromone of the Douglas Fir Tussock Moth both involving tosylhydrazone fragmentation have been reported. 148*149 In one of these (Scheme 9) the epoxide (66) yields the acetylenic ketone (67) which is then converted into (68).14* The synthesis of racemic150 and optically active stere~isomers~~~ of 3,ll -dimethylnonacosan-2-one and 29-hydroxy-3,1 l-dimethylnonacosan-2-one,152.’53 two compounds isolated from virgin females of BZattela germanica have been reported.Phase-transfer methylation of benzyl3-oxobutanoate as a route to 3-methyl-2-alkanones has also been shown to be valuable for the synthesis of these two 0 (68) Reagents i n-CloH21MgBr; ii H30+; iii H202-NaOH-MeOH; iv p-TsNHNH2; v H2-Pd/BaS04 Scheme 9 144 K. Mori T. Takigawa and M. Matsui Tetrahedron Letters 1976 3953. ’*’ D. G. Farnum T. Veysoglu A. M. Cardt B. Duhl-Emswiler T. A. Pancoast T. J. Reifz and R. T. CardC Tetrahedron Letters 1977 4009. 146 F. W. Kuepper and R. Streck 2.Naturforch. 1976 31b 1256. 14’ K. Abe T. Yamasaki N. Nakamura and T. Sakan Bull.Chem. SOC. Japan 1977,50,2792. 14’ P. J. Kocienski and G. J. Cernigliaro J. Org. Chem. 1976,41 2927. 14’ K. Mori M. Uchida and M. Matsui Tetrahedron 1977 33 385. lJ0 L. D. Rosenblum R. J. Anderson and C. A. Henrick Tetrahedron Letters 1976,419. lS1 C. Conti A. Niccoli and R. Rossi Chimica e Industria 1976,58 877. lS2 A. W. Burgstahler L. 0.Weigel M. E. Sanders C. G. Schaefer W. J. Bell and S. B. Vuturo J. Org. Chem. 1977,42,566. lS3 R. Nishida T. Sato and Y. Kuwahara Agric. and Biol. Chem. (Japan) 1976,40 1407. A. W. Burgstahler M. E. Sanders C. G. Schaefer and L. 0.Weigel Synthesis 1977,405. Biological Chemistry -Part (ii) Insect Chemistry Alicyclic Derivatives.-Full details of the synthesis of optically active grandisol (71) one of the four synergistic components of the male Boll Weevil pheromone has been p~blished.'~' Photolysis of (69) obtainable in a series of steps from (-)-P -pinene gave (70) which on decarbonylation using chlorotris(tri-pheny1phosphine)rhodium gave grandisol acetate and subsequently (+)-grandisol (+)-(lR,2S)-l-methyl-l-(2-hydroxyethyl)-2-isopropenylcyclobutane.A process of geminal alkylation involving 1-lithiocyclopropyl sulphide has also been used in a synthesis of grandis01.'~~ H (69) (70) (71) A two-step synthesis of a mixture of the two (3,3-dimethylcyclo-hexy1idine)acetaldehydes (73) two other components of the boll weevil pheromone has been re~0rted.I~~ In this Vilsmeier formylation of isophorone afforded (3-chloro-5,5-dimethylcyclohex-2-enylidene)ace~aldehyde (72) in 80% yield.Catalytic hydrogenation of (72) over palladium on charcoal poisoned with sulphur and quinoline gave a 2 :1 mixture of the E/Z-isomers of (73). Treatment (72) (73) of the reaction product with a catalytic amount of toluene-p-sulphonic acid yielded a 1:1 mixture of stereoisomers. These two compounds together with the other cyclohexyl component (77) have also been prepared from 3-methylcyclohex-2- enone by way of (74)-(76) (Scheme One problem in this synthesis is that (77) the desired alcohol is obtained as a 1 1 mixture with (78); a difficult separation is necessary here. The formation of a P-unsaturated aldehydes by the bishomologation of ketones has also been applied to the synthesis of the aldehyde components of the pheromone mixture.'59 Syntheses of endo- and exo-brevicomin have attracted much attention.Both of them were synthesized by a route involving reaction of the tosylhydrazone formed from the epoxide of 1-ethyl-2-methylcyclohex-l-enone.'60The acetylenic ketone (80)obtained from this reaction has also been obtained by the reaction of (79) with methyl-lithium. The acetylenic ketone was reduced to the cis-olefin (8l) P. D. Hobbs and P. D. Magnus J. Arner. Chem. SOC.,1976 98,4594. B. M. Trost D. E. Keeley H. C. Arndt and M. J. Bogdanowicz J. Amer. Chem. Soc. 1977,99,3088. P. C. Traas H. Boelens and H. J. Takken Rec. Truu. chim. 1976,95 308. lS8 S. W. Pelletier and N. V. Mody J. Org. Chem. 1976 41 1069. lS9 J. H. Babler and J. M. Coghlan Synth. Comm. 1976,6 469.160 P. J. Kocienski and R. W. Ostrow J. Org. Chem. 1976 41 398. J. L. Coke H. J. Williams and S. Natarajan J. Org. Chern. 1977 42 2380. R. Baker and D. A. Evans Reagents i MeZCuLi; ii L~CECH-NH~(CH~)~NH~; iii Ac20-H+; iv 80% AcOH-Ag2C03; v H20; vi 9-BBN or NaBH4 Scheme 10 whence epoxidation and thermolysis gave exo-brevicomin (82) the pheromone from Dendroctonus brevicornis (Scheme 11). The selective irradiation of the Reagents i PCI3; ii MeLi; iii heat; iv m-CIC6H4C03H Scheme 11 carbonyl group of 2-propionyl-6-methyl-2,3-dihydro-4H-pyranhas also been shown to be after hydrogenation a selective and elegant route to exo-brevi- comin.162A further synthesis of (-)-(lS,7S)-exo-brevicornin is rep0~ted.I~~ endo-Brevicomin (83),a pheromone inhibitor has been synthesized by a palladium(I1)- catalysed intramolecular cyclization of a terminal olefin containing a suitably located vicinal diol group (84).'64 162 D.Chaquin J. P. Morizur and J. Kossanyi J. Amer. Chem. SOC.,1977,99 903. H. H. Meyer Annalen 1977 732. '64 N. T. Byrom R. Grigg and B. Kongkathip J.C.S. Chem. Comm. 1976 216. Biological Chemistry-Part (ii) Insect Chemistry 389 &-PdC12-CuC12 OH (83) (84) Both enantiomers of frontalin have been synthesized from the ketone (85) derivable from methyl a-D-glucopyranoside. 165 Thus (lR,SS)-frontalin (90) was prepared through the intermediate compounds (86)-(89). HO (86) Bn =PhCH2 (87) 1 AcO fo\ i,Ph3P CHZOH t a-Multistriatin (92) one of the compounds of the aggregation pheromone of Scolytus multistriutus has been synthesized from (9l) which was available from (Z)-b~t-2-ene-1,4-diol.~~~ A similar route except that (91) was prepared from O# (91) (I?)-( +)-glyceraldehyde obtainable from D-mannitol established the absolute stereochemistry of the natural pheromone to be (1S,2R,4S,5R).'67 The same conclusion was reached as a result of a synthesis beginning with (S)-(+)-2-methyl-but-3-enoic acid.'68 a-Multistriatin has also been synthesized by a route beginning with (+)-(3R)-citronellol although the final product was a mixture of a-y-isomers and gas-chromatographic separation was required.16' The oxidation of pinene was used to prepare optically pure (+)-trans-verbenol the pheromone of Dendroctonus bark beet1es.l" Both enantiomers of cis-verbenol 16' D.R. Hicks and-B. Fraser-Reid J.C.S. Chem. Comm. 1976 869. '66 W. J. Elliot and J. Fried J. Org. Chem. 1976 41 2475. 16' K. Mori Tetrahedron 1976 32 1979. 16' G. T. Pearce W. E. Gore and R. M. Silverstein J. Org. Chem. 1976,41 2797. G. J. Cernigliaro and P. J. Kocienski J. Org. Chem. 1977,42 3622. ''O K. Mori Agric. and Biol. Chem. (Japan) 1976,40,415. R. Baker and D. A.Evans were synthesized from (+)-and (-)-verbenone.171 It was further pointed out that the pheromone of the Ips bark beetle should be described as (lS,4S,SS)-pin-2-en- 4-01 rather than (+)-cis-verbenol since the sign of rotation depends on the solvent enclosed. A general synthesis of optically active 4-alkyl (or 4-alkenyl)-y-lactones from commercially available enantiomers of glutamic acid is reported.172 Both enan- tiomers of S-n-hexadecalactone the pheromone suggested to be responsible for social behaviour of the queens and workers of Vespa orientalis have been prepared from (R)-(+) and (S)-(-)-1,2-epo~ytetradecane.l~~ The epoxides were prepared by resolution of 1-dimethylaminotridecan-2-01 with the enantiomers of dibenzoyl-tartaric acid followed by Hofmann elimination. A termiticidal norsesquiterpenoid dl-chamaecynone (93) has been prepared by a route involving a Diels-Alder reaction of (94) and (95).174 A defensive secretion of the termite Arniterrnes evuncifer 4,ll -epoxy-cis-eudesmane (99) has been synthesized stereospecifically from (-)-carvone (96) in which the key steps were annulation to (97) and oxymercuration to (98).17' Other reported synthesis include those of 2-deoxyecdy~ones'~~ and dl-ne~cembrene.'~~ 0 OH OH (97) 1 17' K.Mori N. Mizumachi and M. Matsui Agric. and Biol.Chem. (Japan) 1976 40 1611. "* U. Ravid and R. M. Silverstein Tetrahedron Letters 1977 423. 173 J. L. Coke and A. B. Richon J. Org. Chem. 1976,41,3516. 174 T. Harayama H. Cho and Y. Inubushi Tetrahedron Letters 1977 3273. 17' R. Baker D. A. Evans and P. McDowell J.C.S. Chem. Comm. 1977 111. 176 J. F. Kinnear M. D. Martin D. H.S. Horn,E. J. Middleton J. S. Wilkie M. N. Galbraith and R. I. Willing Austral. J. Chem. 1976 29 1815. 177 Y. Kitahara T. Kato and T. Kobayashi Chem. Letters 1976 3 219. Biological Chemistry-Part (ii) Insect Chemistry A synthesis of furanoterpenoids involving a 1,4-~ycloaddition reaction of singlet oxygen appears to be generally useful.17' The 2,5-dialkylpyrrolidines which are constituents of the South African Fire Ant Solenopsispunctuticeps have been pre- pared by stepwise alkylation of 2-lithio-1-nitrosopyrrolidines 179 and by photolysis of the appropriate N-chIor~amines.~~ 17' K. Kondo and M. Matsumoto Tetrahedron Letters 1976 390. R. R. Fraser and S. Passannanti Synthesis 1976 540.