- An electrochemical approach to some insect pheromones with (E)-alkene moiety
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An easy access to some Lepidopteran pheromones containing (E)-alkene moiety via anodic oxidation of a partially neutralized mixture of trans-3-alkenoic acids and methyl hydrogen carboxylates has been described.
- Singh, Krishna Nand,Singh, Manorama,Misra, Ram Achal
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p. 431 - 434
(2007/10/02)
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- Preparation of 9-alkenyl ester compounds
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Process for the production of 9-alkenyl acetates is provided. The process comprises first disproportionating cyclooctene with an α-olefin to give a 1,9-alkadiene. The alkadiene is metallated to form a 1-metallo-9-alkene, which is then contacted with oxygen to produce a 9-alkenyl-1-oxymetallo compound, which is optionally hydrolyzed to the corresponding alcohol, with the alcohol being esterified to the desired 9-alkenyl ester or the 9-alkenyl-1-oxymetallo compound can be directly esterified, to produce the desired 9-alkenyl esters.
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- SYNTHESIS OF PHEROMONES, IV. CHEMISTRY OF THE WITTIG REACTION, I. EFFECTS OF REACTION CONDITIONS ON THE STEREOSELECTIVITY AND YIELD OF THE WITTIG REACTION
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The reactions of nonstabilized triphenylphosphorus ylides with aldehydes have been studied in detail.The stereochemistry and yields of the alkene products are highly dependent upon base used for the generation of the ylide, the solvent and reaction temperature.The synthesis of sex pheromone components by Wittig reaction are also described.
- Vinczer, Peter,Juvancz, Zoltan,Novak, Lajos,Szantay, Csaba
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p. 797 - 820
(2007/10/02)
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- Metathesis of Functionalized Alkenes. Synthesis of Insect Pheromones
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The ability of substituted phenoxy complexes of tungsten to effect metathesis of both functionalized and non-functionalized terminal alkenes has been investigated.This methodology has been applied to the synthesis of the insect pheromones tetradec-9-en-1-yl acetate, dodec-7-en-1-yl acetate and tricos-9-ene.
- Crisp, Geoffrey T.,Collis, Maree P.
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p. 935 - 942
(2007/10/02)
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- Disproportionation of functional olefins
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A process for producing functional monoolefins having specific types of cis to trans ratios involving disproportionating a functional monoolefin with a hydrocarbyl monoolefin consisting essentially of either (1) an internal olefin or (2) a terminal olefin. Also disclosed are functional olefin compositions useful in controlling insects.
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- A General Approach to the Synthesis of Mono-olefinic Insect Sex Pheromones of Z- or E-Configuration
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A series of insect sex pheromones and structually related olefins have been synthesized with high stereoisomeric purity by two sequential cross-coupling reactions.Starting with (Z)- or (E)-1-bromo-2-phenylthioethene, (1) and (2), and Grignard reagents in the presence of nickel or palladium catalysts, two types of compounds have been prepared: (i) 1,2-dialkylethenes and (ii) alkenyl acetates.In the synthesis of Z-isomers, the first step involves a cross-coupling reaction of compound (1) with the appropriate Grignard reagent in the presence of a catalytic amount of .The second cross-coupling reaction is performed on the intermediate (Z)-phenylthioalkenes using a different Grignard reagent in the presence of (dppe=Ph2PCH2CH2PPh2) as a catalyst.In the synthesis of E-isomers both steps are cross-coupling reactions of Grignard reagents in the presence of as a catalyst, the first step involving compound (2) and the second step involving the intermediate (E)-phenylthioalkenes obtained.The Grignard reagents used in the synthesis of the alkenyl acetates derive from protected ω-halohydrins.
- Fiandanese, Vito,Marchese, Giuseppe,Naso, Francesco,Ronzini, Ludovico
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p. 1115 - 1120
(2007/10/02)
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- Polymer-anchored Organosilyl Protecting Group in Organic Synthesis
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Polymer-anchored dimethyl- and diphenyl-chlorosilanes (1a) and (1b) have been prepared and polymer (1b) was found to be useful for the protection of the hydroxy functional group; its use in the synthesis of an insect sex pheromone is reported.
- Chan, Tak-Hang,Huang, Wen-Qiang
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p. 909 - 911
(2007/10/02)
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- A Convenient Synthesis of (E)-9-Tetradecen-1-yl Acetate, a Sex Pheromone of Gelechiid Moth and (E)-5-Decenol, a Sex Pheromone of Peach Twig Borer
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n-Butyllithium reacts with dihydropyran to give (E)-4-nonenyl alcohol (IV).The alcohol (IV) is converted into the corresponding bromide (V).The Grignard reagent of the bromide (V) on coupling with the bromide (VI) in the presence of Li2CuCl4, followed by hydrolysis yields the alcohol (III).This on acetylation gives the pheromone (I).The formylation of the Grignard reagent prepared from V gives the pheromone (II).
- Chattopadhyay, A.,Mamdapur, V. R.,Chadha, M. S.
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p. 1221 - 1223
(2007/10/02)
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- Olefin Inversion. 3. Preparations and Reductions of vic-Halohydrin Trifluoroacetates
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Treatment of alkenes with N-bromo- and N-chlorosuccinimide in trifluoroacetic acid resulted in stereospecific anti addition of the elements of trifluoroacetyl hypobromite and hypochlorite, respectively.Heating the vic-bromo- or -chlorohydrin trifluoroacetates with NaI in DMF produced olefins with inversion of geometry.Treatment of the adducts with Zn in DMF reduced them to olefins with retention of geometry.Reductive transformations involving the chlorohydrin trifluoroacetates were virtually stereospecific, whereas those involving the bromohydrin trifluoroacetates were >90percent stereoselective for NaI reductions and only 60-90percent stereoselective for reductions by Zn.
- Sonnet, Philip E.
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p. 154 - 157
(2007/10/02)
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- INSECT SEX PHEROMONES. STEREOSELECTIVE SYNTHESIS OF SEVERAL (Z)- AND (E)-ALKEN-1-OLS, THEIR ACETATES, AND OF (9Z,12E)-9,12-TETRADECADIEN-1-YL ACETATE
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Several female sex pheromone components produced by moths belonging to the order of Lepidoptera, and potential attractants of Dacus oleae (Diptera:Tripetidae) have been synthesized in high chemical and stereoisomeric purity by improved acetylenic routes involving alkylation of lithium 1-alkyn-1-ides in HMPT, followed by (Z) and (E) highly stereoselective reduction of the derived internal alkynes.Particular care has been paid to optimize the parameters of the reactions used and to evaluate the chemical and isomeric purity of the reaction products.The compounds synthesized include (Z)- and (E)-5-nonen-1-ol, (Z)- and (E)-7-dodecen-1-yl acetate, (Z)- and (E)-7-teradecen-1-yl acetate, (Z)- and (E)-7-nonen-1-ol, (Z)- and (E)-9-tetradecen-1-yl acetate, (Z)- and (E)-10-tetradecen-1-yl acetate, (Z)- and (E)-11-tetradecen-1-yl acetate.Pure (Z)-6-nonen-1-ol, which is an attractant of olive fruit fly, D. oleae, and very probably, a constituent of the sex pheromone of females of this insect, has been prepared by a rather efficient copper-catalyzed reaction between (Z)-3-hexen-1-ylmagnesium bromide and oxetane. (9Z,12E)-9,12-Tetradecadien-1-yl acetate, which is the pheromone of Anagasta kuenniella, Ephestia elutella, Cadra figulella, Spodoptera exigua, S. litura, and a component of the sex pheromones of several other Lepidoptera, has been conveniently prepared by using the copper-catalyzed coupling reaction between (E)-1-chloro-2-butene and 10-tetrahydropyranyloxy-1-decenylmagnesium bromide, followed by acetylation and Z-stereoselective reduction of the derived 1,4-enyne.All syntheses have been conducted on a scale to yield less than 50 mmol of the pure sex pheromone components, but seem adaptable for much larger quantities.
- Rossi, Renzo,Carpita, Adriano,Gaudenzi, Loretta,Quirici, Maria Grazia
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p. 237 - 246
(2007/10/02)
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