Identification and synthesis of new sex-specific components of olive fruit fly (Bactrocera oleae) female rectal gland, through original Negishi reactions on supported catalysts

Abstract

Graphical AbstractIdentification and synthesis of new sex specific components of olive fruit fly (Bactrocera oleae) female rectal gland, through original Negishi reactions on supported catalysts Identification and synthesis of new sex-specific components of olive fruit fly (Bactrocera oleae) female rectal gland, through original Negishi reactions on supported catalystsIn the present study, eleven new sex-specific components extracted from female rectal gland of olive fruit flies were synthesized and identified. The quantitative determination of those components by GC and GC/EI-MS, at different moments of the insect life span, highlighted the growing trend of their secretion. While for the synthesis of saturated esters, conventional transesterification methods could be adopted, for the synthesis of unsaturated components, a Negishi cross-coupling between organozinc halides and (Z)-1-bromo-alkenes was developed. To the extent of our knowledge, this reaction represents the first example of catalyst-supported Negishi coupling, between an alkyl electron donor and an alkenyl electron acceptor..

From Insect Pheromones to Mating Disruption

“…Bioassays involving the synthetic enantiomers of oleane showed that (R)-oleane is active on males, while (S)-oleane on females, and GC analyses showed that females can produce (±)-oleane [206]. The synthesis of enantiomers of 4-hydroxyoleanes was conducted by Mori and co-workers [284] and a recent study identified and synthesised 11 new B. oleae female-specific components [285].…”

Tephritid Fruit Fly Semiochemicals: Current Knowledge and Future Perspectives

“…Bioassays involving the synthetic enantiomers of oleane showed that ( R )-oleane is active on males, while ( S )-oleane on females, and GC analyses showed that females can produce (±)-oleane [ 207 ]. The synthesis of enantiomers of 4-hydroxyoleanes was conducted by Mori and co-workers [ 286 ] and a recent study identified and synthesised 11 new B. oleae female-specific components [ 287 ].…”

Total Synthesis of Asparenydiol by Two Sonogashira Cross-Coupling Reactions Promoted by Supported Pd and Cu Catalysts

“…8 Today, the Sonogashira reaction is commonly performed under homogeneous catalysis conditions; 9 it does not require preformed organometallic acceptor species in stoichiometric amounts, as in the case of Negishi cross-coupling reactions, 10 which is also used for the synthesis of natural compounds. 11 For larger-scale and greener applications of the Sonogashira reaction, several methods have been developed, including copper-free reactions, solvent-less reac-tions, and, notably, Pd-based supported catalysts such as Pd/C. 12 Depending on the order of disconnection between B and C, the structure of the intermediates could change (12 or 4), even though the building blocks to obtain 8 are essentially the same; 4-tert-butyldimethylsilyl-1-iodobenzene (2), (E)-3-bromoacrylate (7) and trimethylsilylacetylene (13).…”

“…28,29 The reaction conditions were initially optimized using Pd EnCat TM 40 as a catalyst (Table 1), because this was already successfully tested for the synthesis of some natural compounds. 11,30 We initially tried to perform the reaction in the absence of copper (Table 1, entry 1), however, although the starting material disappeared after 3.5 h, many different side-products were formed, and a low yield of the desired product was obtained. The reaction was therefore tested under more classical Sonogashira conditions with a 2:1 ratio between palladium and copper, but with reduced catalyst loading (0.5 mol% of Pd; entries 2-4); also in this case, after 5 h, many collateral reactions took place.…”

“…MS (EI) m/z (%) = 225 (4), 224 (20) [M] + , 169 (6), 168 (22), 167 (100), 153 (2), 137 (3), 75 (5), 73 (3). (E)-tert-Butyl(4-(5-(4-((tert-butyldimethylsilyl)oxy)phenoxy)pent-3-en-1-yn-1-yl)phenoxy)dimethylsilane(11)…”