Stereocontrolled Synthesis of the Sex Pheromone of Nezara viridula (L.)

Abstract

The main component of the green stink bug Nezara viridula (L.) sex pheromone, the (Z)-(lS,2R,4S)-(-)-epoxybisabolene (l), has been synthesized by a convergent stereocontrolled sequence, using (S)-(-)-periUyl alcohol (2) as starting material.The southern green stink bug (or green vegetable bug) Nezara viridula (L.) is an important pest of several agricultural crops, and nowadays it is distributed throughout many parts of the world, specially in tropical and neotropical regions [']. It attacks a wide range of vegetables, fruits and cereal cultures, damaging the most valuable portion of a crop, the seeds and the fruits. For example, in soybean cultures, one of the preferable targets of these insects, both the adult and immature bugs feed on seeds by sucking oil through a hypodermic-like mouthpart, provoking significant reductions in the quantity and in the quality of the oiP21.The euryphytophagous behavior of the stink bugs has made their control extremely difficult. The pyrethroids and systemic phosphorous insecticides are still used worldwider3], but efforts have been made to find alternative ways to control them. Some recently investigated control techniques include trap crops, specially in soybean and, in the area of biological control, the use of A! viridula natural parasitoids as Trichopoda pennipes (F.) and Trissolcus basalis (W.)[3b,c,51. Another possibility, always considered for insect population control, is the use of chemical attractants such as sexual pheromones.The first notice about A! viridula sex attractants was reported in 1971r61, indicating that the male produces a sex pheromone highly attractive to females and also to its natural parasitoid Trichopoda pennipes. Nowadays it is known that the pheromone chemical composition depends on the A! viridula origin [7], but all blends include trans-(2)-a-bisabolene epoxide, (2)-a-bisabolene, n-nonadecane, and several less abundant alkanes. trolling them, we decided to undertake a new stereocontrolled synthesis of this A convergent route to 1 was designed (Scheme l), and for the construction of the bisabolene skeleton with the desired double bond geometry Z we proposed a Homer-Wittig reaction of the ketone 7 with the phosphane oxide 13. The p-menthane ketone 7 with the asymmetric centers 1S,2R,4S was prepared by using the commercially available (S)-( -)-perilly1 alcohol (2) as starting material.The asymmetric epoxidation of the allylic alcohol 2 (Scheme 2) was successfully achieved by means of the Sharpless-Katsuki method, and 3 was obtained in 93% yield and 94% d.e. (determined by GC analyses) when a slight excess of the catalysts Ti(OiPr)4 and (-)-diethy1 tartrate was used ['0]. The assignment of the epoxide stereochemistry was based on the expected mode of reaction and was confirmed later, when 3 was transformed into the compound 71"l (Scheme 2 -total yield 47% based on perillyl alcohol 2). It must be emphasized that the 0-mesyl derivative 5 obtained from 3 as a crystalline solid (99% yield) showed only one peak by GC analyses (R, = 16.1 min), indicatin...

Syntheses of Insect Sex Pheromones. A Review of the Literature 1990-1998

“…For instance, a new synthesis of Nezara viridula sex pheromone blend and the intermediate for its preparation can be found in the papers of Kuwahara et al 175 and Ceccherelli et al 176 . While the former authors based their syntheses on the similar principle as Baptistella 43 …”

Química Orgânica no Brasil: sua contribuição na síntese total de produtos naturais desde a fundação da SBQ

“…É o caso da maria-fedida ou pecervejo-da-soja (Nezara viridula Linnaeus). O sesquiterpeno bisaboleno de estereoquímica (Z)-(1S,2R,4S) foi sintetizado a partir do álcool perílico e empregou uma reação de olefinação 14 , bastante comum na preparação de insaturações em compostos atrativos de insetos. Outro inseto com componente único no feromônio atrativo que teve seu feromônio sintetizado foi o caruncho-do-fumo (Lasioderma serricorne Fabricius).…”

Highly Stereoselective Synthesis of the Sex Pheromone Components of the Southern Green Stink Bug Nezara viridula (L.) and the Green Stink Bug Acrosternum hilare (Say)

“…[2][3][4] In view of the importance of these insects as agricultural pests, and the important role that the pheromones could play in the development of attractant-based methods of monitoring and controlling these bugs, 1 and 2 have attracted the interest of synthetic chemists, and at least six syntheses have been described. [3][4][5][6][7][8] However, all the reported syntheses have major drawbacks, varying from the production of the epoxybisabolenes as mixtures of several or all possible stereoisomers, 4,6 to the production of small quantities of compounds from lengthy syntheses requiring highly toxic and/or expensive reagents. 3,5,7,8 The resulting lack of significant quantities of stereochemically pure compounds has delayed the determination of the optimal pheromone blend for each species, and field testing of the blends to assess their potential for development into pest management tools.…”

“…[3][4][5][6][7][8] However, all the reported syntheses have major drawbacks, varying from the production of the epoxybisabolenes as mixtures of several or all possible stereoisomers, 4,6 to the production of small quantities of compounds from lengthy syntheses requiring highly toxic and/or expensive reagents. 3,5,7,8 The resulting lack of significant quantities of stereochemically pure compounds has delayed the determination of the optimal pheromone blend for each species, and field testing of the blends to assess their potential for development into pest management tools. Our objective was to develop straightforward preparative scale methods for synthesizing the target compounds in high chemical and isomeric purity, to provide sufficient quantities of pure materials for laboratory bio-assays and field tests.…”

“…Horner−Wittig reaction between the lithium salt of (4-methyl-3-pentenyl)diphenylphosphine oxide (5) 7 and β-epoxy ketone 4a in THF at −78 °C afforded the desired erythro-adduct 6 as the major product, 10 together with (E)-(1R,2S,4S)-epoxybisabolene 7 as a minor product. However, the choice of base was critical: with n-butyllithium, 7 the yield of 6 was poor, and most of the unreacted ketone 4a was racemized at C-4. An improvement in yield (61%) was achieved by substituting LDA for n-BuLi, with no epimerization of the small amounts of unreacted ketone 4a.…”