Synthesis of Insect Sex Pheromones and Their Homologues I. (Z,E)-9, 11-Alkadienyl Acetates

(Z, E)-9, 11-Tetradecadienyl-l-acetate (1), a major component of the sex pheromone of Spodoptera litura (F.), and (Z, E}-9, 11-pentadecadienyl-1-acetate (2) were synthesized by the Wittig reaction between (E)-2-alkenal (3) and the ylid derived from 9-hydroxynonyltriphenylphosphonium bromide (4).     

Stereocontrolled Conversion of 3,5-Dioxopyrrolizidine Into (Z)- and (E)- 5-Acetonylpyrrolizidin-3-ones

Stereocontrolled synthesis of (Z)-5-acetonyl-pyrrolizidin-3-one (4) and (E)-isomer 5 from 3,5-dioxopyrrolizidine 1 is described.     

Reductive Cleavage of 2-Acyl Tetrahydrofuranes. Synthesis of (Z)-6-Heneicosen-11-one,Pheromone of the Douglas Fir Tussock Moth

(Z)-6-heneicosen-11-one was prepared using the reductive cleavage of 2-tetrahydrofuryldecylketone 6 to 5-oxo-pentadecan-1-ol 7 as the key step of the synthesis.     

A Convenient Synthesis of (1 1E, 13E)-11, 13-Hexadecadienal and (11Z, 13E)-Hexadecadienal

A simple method for synthesizing (11E, 13E)-11, 13-hexadecadienal 7, a component of the female sex pheromone of cabbage webworm, and its geometrical isomer (11Z, 13E)-11, 13-hexadecadienal 8 is described.     

Pheromone XXXVII. Eine stereospezifische synthese der komponenten des sexualpheromons von antherea polyphemus, (E)-6,(Z)-11-hexadecadienylacetat und (E)-6,(Z)-11-hexadecadienal.

Starting from the aldehydes $\text{2}$ and $\text{9}$ the acetylene $\text{16}$ is prepared via the borane $\text{15}$ by means of a combined Wittig reaction-hydroboration reaction sequence. $\text{16}$ may be converted into the (E)-6,(Z)-11-hexadecadienylacetate ($\text{18}$) and the corresponding aldehyde $\text{19}$. The synthetic route proceeds with high stereospecifity (isomeric purity of $\text{18}$ and $\text{19}$ ? 97%).     

Synthesis of (Z)- and (E)-3,4-Dimethyl-hex-3-ene-1,6-diols

(Z)- and (E)-3,4-dimethyl-hex-3-ene-1,6-diols (1 and 2) have been synthesized in 23% and 68% yields by a three step sequence requiring only one purification at the end. The steps are a) coupling of 2-lithio-1,3-dithiane with (Z)- or (E)-1,4-dibromo-2,3-dimethyl-but-2-ene (3 or 4), b) hydrolysis of the thioketals (8 and 9) with methyl iodide in a mixture of acetonitrile, acetone and water to give the 3,4-dimethyl-hex-3-ene-1,6-diols (10 and 11) and c) reduction with diisobutylaluminum hydride to provide the (Z)- and (E)-diols.     

(E)- and (Z)-1-benzenesulfonyl-4-trimethylsilyl-2-butenes as (E)-1-(1,3-butadienyl) synthons

(E)- and (Z)-1-benzenesulfonyl-4-trimethylsilyl-2-butenes (E/Z=9), prepared from 4-trimethylsilyl-1-buten-3-ol, $\text{n}$-butyllithium and benzenesulfenyl chloride and oxidation of the intermediate (E)- and (Z)-1-benzenesulfinyl-4-trimethylsilyl-2-butenes with hydrogen peroxide, react with $\text{n}$-butyllithium and then primary halides to give 4-benzenesulfonyl-1-trimethylsilyl-2-alkenes which are rapidly 1,4-debenzenesulfonyltrimethylsilated to (E)-1,3-alkadienes by tetra-$\text{n}$-butylammonium fluoride at O°C.     

Synthesis of (Z)-3-Butylidene-4-hydroxyphthalide

(Z)-3-Butylidene-4-hydroxyphthalide (5) was first synthesized regio- and stereoselectively from 3-methoxybenzyl alcohol (1)     

Diepoxy[18]annulene(10.0) : (Z,E,Z,E,Z)‐Diepoxy[18]annulen(10.0) – ein hochdynamisches Annulen

Diepoxy[18]annulenes(10.0): ( Z , E , Z , E , Z )‐Diepoxy[18]annulene(10.0) – a Highly Dynamic Annulene The McMurry reaction of (all‐E)‐5,5′‐([2,2′‐bifuran]‐5,5′‐diyl)bis[penta‐2,4‐dienal] ( 13 ) only occurs intramolecularly to give a mixture of the diepoxy[18]annulenes(10.0) 6 and 7 . Tetraepoxy[36]annulene(10.0.10.0) resulting from an intermolecular McMurry reaction is not formed. According to spectroscopic data, 6 is (Z,E,Z,E,Z)‐ and 7 (Z,E,E,Z,E)‐configured. The ¹H‐NMR data confirm that in 6 the (E)‐ethene‐1,2‐diyl bonds (C(11)=C(12) and C(15)=C(16)) rotate around the adjacent σ‐bonds. Beginning at −70°, this rotation freezes, and 6 is becoming a diatropic aromatic ring system. Beside [18]annulene itself, (Z,E,Z,E,Z)‐diepoxy[18]annulene(10.0) 6 is the only hitherto known [18]annulene derivative with dynamic properties.     

Sex Pheromone of Chilo Suppressalis: Efficient Syntheses of (Z)-11-Hexadecenal, (Z)-13-Octadecenal And (Z)-9-Hexadecenal

The constituents of the sex attractant pheromone of Chilo suppressalis: (Z)-11-Hexedecenal 1, (Z)-13-octadecenenal 2 and (Z)-9-Hexadecenal 3 have been synthesized as their ethylene acetals 19, 15 and 13, in six steps from easily available compounds. The synthetic methodology can be applied to preparative scale.     

Synthesis of anacardic acids, 6-[8(Z),11(Z)-pentadecadienyl]salicylic acid and 6-[8(Z),11(Z),14-pentadecatrienyl]salicylic acid

11-Chloro-3-methoxy-2-undecenal was synthesized from 8-bromooctanol, and an annelation reaction with this aldehyde and ethyl acetoacetate proceeded to give the ethyl 6-(8-chlorooctyl)salicylate. Ethyl 6-(8-chlorooctyl)salicylate was converted to ethyl 6-(7-formylheptyl)-2-methoxybenzoate through the iodide after protection of the phenolic hydroxyl group. Finally, the Wittig reaction with the aldehyde and triphenylphosphonium iodides in the presence of BuLi gave the methoxybenzoates, and then treatments of these methoxybenzoates with BBr3 in CH2Cl2 and 10% NaOH in ethanol gave 6-18(Z),11(Z)-pentadecadienyllsalicylic acid (anacardic acid 3) and 6-[8(Z),11(Z),14-pentadecatrienyl]salicylic acid (anacardic acid 4) which were isolated from plants of the anacardiaceae.     

Candidate Trail Attractants of Reticultermes lucifugus: Stereoselective Syntheses of (3Z, 6E,BE)-(3Z, 6E, 8Z)-and (3Z, 6Z, 8Z)-3,6,8 -Dodecatrien-1-OL1

Stereoselective syntheses on a gram scale of (3Z,6E,8E)-, (3Z,6E,8Z)-and (3Z,6Z,8Z)-3,6,8-dodecatrien-1-ol, 8, 9 and 10, respectively, are described. A key step of the synthesis of 8 consisted of a copper-mediated coupling reaction between 4-(2-tetrahydropyranyloxy)-1-butynylmagnesium bromide (15) and the mesyl ester of (2E,4E)-2,4-octadien-1-ol (14). A similar copper-mediated reaction between 15 and the mesyl ester of (E)-2-octen-4-yn-1-ol (19) was used to construct the C-12 carbon skeleton of 9. On the other hand, the synthesis of 10 was based on a palladium-promoted reaction between (Z)-1-bromo-1-pentene (23) and the organozinc bromide derived from 3,6-heptadiyn-1-yl acetate (27).     

Stereoselective Synthesis and Diels-Alder Reactions of (Z)- and (E)-1,2-bis(Phenylthio)-1,3-Butadiene

Bromination of 3-phenylthio-2-sulfolene (2) with N-bromosuccinimide gave 2-bromo-3-phenylthio-2-sulfolene (3) which was converted mainly to 2,3-bis(phenylthio)-2-sulfolene (4) by treatment with sodium phenylthiolate. Thermal desulfonylation of 4 at different temperatures in the presence of a base (DBU) yielded stereoselectively the (Z)- and (E)-1,2-bis(phenylthio)-1,3-butadiene (6). These two geometric isomers could be thermally interconverted. The Diels-Alder reactions of 6 were also investigated. Only the (Z)-diene 6a could undergo the Diels-Alder reaction; the (E)-diene 6b was in situ converted to the Z isomer before undergoing (he Diels-Alder reaction. The reaction of 6a with N-phenylmaleimide gave the cycloaddition product 7 with complete endo selectivity, but under daylight or during chromatography it readily underwent a thioallylic rearrangement to yield 8 with inversion of configuration. The cycloaddition of 6a with methyl acrylate proceeded regiospecifically, but generating a mixture of endo and exo isomers. The endo/exo ratio could be increased by using ZnCl₂ as the catalyst.     

A Novel Approach to the Synthesis of 7(Z), 11(Z)-Nonacosadiene,Pheromone of Drosophila Melano Gaster and 9(Z)-Tricosene,Pheromone of Musca Domestica

The synthesis of 7(Z), 11(Z)-Nonacosadiene (1), the pheromone¹ of Drosophila melanogaster has been reported² recently from a tetrahydrophyridine derivative involving a silicon induced fragmentation reaction as the crucial step. 9(Z)-Tricosene (2) also known as Muscalure and Muscanone is the biologically most active hydrocarbon, isolated from the extracts of cuticular and fecal lipids of sexually mature female houseflies, Musca Domestica. Several synthetic approaches³ for the synthesis of (2) have been reported in the literature. In this communication, we wish to report a novel synthetic approach for the pheromones (1) and (2), employing stepwise alkylation of N,N-dimethylacetone hydrazone (3) as the key step of the synthesis.     

Über die Temperaturabhängigkeit der 13C-NMR.-Spektren von [5–6-η-(1Z, 5E)-Cyclooctadien]tetracarbonyleisen und (1Z, 5E)-Cyclooctadien

On the Temperature Dependence of the ¹³C-NMR. Spectra of [5-6-η-(1Z,5E)-Cyclooctadien] and of (lZ, 5E)-Cyclooctadiene The activation parameters of the conformational ring inversion process (simultaneous rotation around the C(3), C(4) and C(7), C(8) bonds; cf. Scheme 1) of the title compounds ( 1 and 2 , respectively) have been determined between 275 L and 155 K by a complete line shape analysis of the temperature dependent proton noise-modulated decoupled ¹³C-NMR. spectra of 1 and 2 . The temperature dependence of the rates (k( 1 ) and k( 2 ), respectively) of the inversion process can be described by the following equations (no influence of the solvents was observed; E_a in J/mol): . Further data are given in Tables 1 and 2. The carbonyl groups of the complex 1 show at 180 K , where the ring inversion process is frozen out, a single line at 211 ppm, i. e. the coalescence temperature of the carbonyl groups must be < 180 K .     

Metal-catalyzed coupling reactions on an olefin template: the total synthesis of (13E,15E,18Z,20Z)-1-hydroxypentacosa- 13,15,18,20-tetraen-11-yn-4-one 1-acetate

The naturally occurring ant venom (13E,15E,18Z,20Z)-1-hydroxypentacosa-13,15,18,20-tetraen-11-yn-4-one 1-acetate was synthesized stereospecifically using a series of metal-mediated cross-coupling reactions. The use of the difunctional olefin template (E)-1-chloro-2-iodoethylene as the central, pseudosymmetrical building block facilitated a fully convergent and, thus, efficient strategy to prepare this polyunsaturated natural product.     

The electron affinities of (E)- and (Z)-cyclooctene. Preliminary communication

Electron transmission measurements yield vertical electron affinities of ?1.93 eV for (Z)- and of ?1.79 eV for (E)-cyclooctene ( Z and E , respectively). It is concluded that the ‘out of plane’ bending effect in torsioned E does not influence its LUMO-energy to a larger degree than its HOMO-energy (as determined by photoelectron ( PE .) spectroscopy) with respect to non-torsioned Z .     

Synthesis of (Z/E)-11-tetradecen-1-ol, a component of Ostrinia nubilalis sex pheromone

11-Tetradecen-1-ol acetate is a mixture of geometric isomers with the Z/E-conformations in a 94:6 ratio that is used as an attractant to trap corn pests. It has a powerful attractive action similar to that of an isomeric mixture of 11-tetradecenyl acetate with the Z/E-conformation in a 95:5 ratio that was extracted from the peritoneal cavity of male Ostrinia nubilalis Hubner in Xinjing (PRC). __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 177–178, March–April, 2008.     

Straightforward Preparation of (2E,4Z)-2,4-Heptadien-1-ol and (2E,4Z)-2,4-Heptadienal

Abstract

A concise synthesis of (2E,4Z)-2,4-heptadien-1-ol and (2E,4Z)-2,4-heptadienal is presented. Commercially available (Z)-2-penten-1-ol was converted to ethyl-(2E,4Z)-2,4-heptadienoate by reaction with activated MnO₂ and (carboethoxymethylene)triphenylphosphorane in the presence of benzoic acid as a catalyst. Ethyl-(2E,4Z)-2,4-heptadienoate was converted to (2E,4Z)-2,4-heptadien-1-ol with LiAlH₄. The alcohol was partially oxidized to (2E,4Z)-2,4-heptadienal with MnO₂. The title compounds are male-specific, antennally active volatile compounds from the Saltcedar leaf beetle, Diorhabda elongata Brulle (Coleoptera: Chrysomelidae) and have potential use in the biological control of the invasive weed saltcedar (Tamarix spp).