- A general strategy for the stereocontrolled preparation of diverse 8- and 9-membered Laurencia -type bromoethers
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A unique procedure to effect a ring-expanding bromoetherification process is described, wherein tetrahydrofurans and tetrahydropyrans are smoothly transformed into 8- and 9-membered bromoethers in a regio- and stereocontrolled manner through the use of BDSB (bromodiethylsulfonium bromopentachloroantimonate). These products resemble the cores of the Laurencia C15 acetogenins. In light of the generality and effectiveness of the approach, this work provides a unique strategy for their laboratory preparation and may implicate a possible biosynthesis pathway.
- Snyder, Scott A.,Treitler, Daniel S.,Brucks, Alexandria P.,Sattler, Wesley
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p. 15898 - 15901
(2011/11/13)
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- Stereochemically controlled Synthesis of Unsaturated Alcohols by the Horner-Wittig Reaction
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Single isomers (E or Z) of unsaturated alcohols with two to five carbon atoms between the double bond and the OH group may be made by the phosphine oxide version of the Horner-Wittig reaction.Hydroxyalkyldiphenylphosphine oxides react with aldehydes either directly or as silyl ethers to give a moderately Z-selective synthesis, while rearrangement of esters of the same alcohols by acyl transfer or acylation of alkyldiphenylphosphine oxides with lactones gives hydroxy ketones whose reduction and elimination leads to an E-selective synthesis.In most cases, separation of the diastereoisomers of the Horner-Wittig intermediates leads to the preparation of pure E- or Z-alkenols.
- Ayrey, Peter M.,Bolton, Michael A.,Buss, Antony D.,Greeves, Nicholas,Levin, Daniel,et al.
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p. 3407 - 3418
(2007/10/02)
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- OZONOLYSIS OF ALKENES AND REACTIONS OF POLYFUNCTIONAL COMPOUNDS. XXXV. SYNTHESIS OF 8Z-DODECENYL- AND 11Z-TETRADECENYL ACETATES FROM THE CYCLIC DIMER OF BUTADIENE
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The stereoselective synthesis of 8Z-dodecenyl- and 11Z-tetradecenyl acetates which are components of the sex pheromones of many species of insect of the order Lepidoptera, was realized on the basis of the partial ozonolysis of (Z,Z)-1,5-cyclooctadiene and its isomerization product (Z,Z)-1,3-cyclooctadiene.
- Odinokov, V. N.,Ishmuratov, G. Yu.,Galeeva, R. I.,Kharisov, R. Ya.,Sokol'skaya, O. V.,at al.
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p. 646 - 651
(2007/10/02)
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- SYNTHESIS OF SINGLE ISOMERS (E OR Z) OF UNSATURATED ALCOHOLS BY THE HORNER-WITTIG REACTION
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Single isomers (E or Z) of homoallylic and higher alcohols can be synthesised from ω-hydroxyalkyldiphenylphosphine oxides and aldehydes, or from alkyldiphenylphosphine oxides and lactones
- Buss, Antony D,Greeves, Nicholas,Levin, Daniel,Wallace, Paul,Warren, Stuart
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p. 357 - 360
(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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