- Allylsilane-vinylcopper reagents: Palladium-mediated coupling with alkenyl halides. Synthesis and photochemical [2+2] cyclization of (±)-Ipsdienol
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Reaction of phenyldimethylsilyl-copper with 1,2-propadiene followed by Pd0 catalyzed coupling of the resulting copper intermediate with alkenyl halides affords allylsilane-containing dienes in high yield. Coupling with vinyl bromide gives 2-phenyldimethylsilylmethylbuta-1,3-diene which is an isoprenyl building block for the synthesis of (±)-Ipsenol and (±)-Ipsdienol, the aggregation pheromones of the Ips bark beetle. The photochemical [2+2] cyclization of Ipsdienol was also studied.
- Barbero,García,Pulido
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- 1,2-ELIMINATION OF ALCOHOL FROM HOMOALLYL ETHERS UNDER THE INFLUENCE OF MIXED METAL BASES
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Lithium diisopropylamide in the presence of catalytic amounts of potassium tert-butoxide smoothly converts homoallyl or homobenzyl type ethers to dienes (e.g., 1, 3, 5, 26) or styrenes (2). γ,δ-Unsaturated acetals give 1,3-dienyl ethers (e.g., 4) and 4-alkylidenetetrahydropyrans or dihydropyrans produce a variety of dienols (e.g., 6 - 17, 20 - 22). - If there is a choice, the new double bond is formed with high trans-selectivity while the configuration of existing double bonds is retained. - The elimination mode is syn-periplanar and concerted, though E1cb like.
- Margot, Christian,Rizzolio, Michele,Schlosser, Manfred
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- A REGIO- AND STEREOCONTROLLED ACCESS TO 2,4-DIENOLS BY AMIDE/ALCOHOLATE-PROMOTED RING-OPENING OF DIHYDRO-PYRANS
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3,6-Dihydro-2H-pyrans and other, cyclic or acyclic, homoallyl ethers undergo smooth ring-opening through β-elimination when treated with lithium diisopropylamide in the presence of catalytic amounts of potassium tert-butoxide.
- Margot, Christian,Schlosser, Manfred
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- New preparation of reactive zinc metal by electrolysis and its use for a facile isoprenylation of aldehydes and ketones
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Reactive zinc metal can be prepared by the electrolysis of a DMF solution containing Et4NClO4 with a platinum cathode and a zinc anode. The reaction of 2-bromomethyl-1, 4-dibromo-2-butene (1) with aldehydes or ketones in the presence of the electrogenarated reactive zinc (EGZn) in DMF at 0 °C gave the corresponding isoprenylated alcohols (3a-3n) in good yields.
- Tokuda, Masao,Mimura, Nobuo,Karasawa, Tamae,Fujita, Hirotake,Suginome, Hiroshi
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- 2-DIPROPYLBORYLMETHYL-1,3-BUTADIENE - A NEW REAGENT FOR ISOPRENYLATION. EFFICIENT SYNTHESIS OF IPSENOL AND IPSDIENOL
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A simple and convenient method for isoprenylation of carbonyl compounds and ethoxyacetylene using the titled new boron containing "isoprene C-5 synthon" and application of this efficient procedure to the synthesis of ipsenol and ipsdienol are described.
- Bubnov, Yuri N.,Etinger, Marina Yu.
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- Convenient isoprenylation of aldehydes and ketones: Synthesis of (±)-ipsdienol and (±)-ipsenol
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The reaction of 2-bromomethyl-1,4-dibromo-2-butene (1) with various aldehydes and ketones in tetrahydrofuran containing zinc powder under reflux gave the corresponding isoprenylated alcohols 3a-o in one step in good yields. The synthesis of ipsdienol (3e) and ipsenol (3c) was achieved by the present method starting from 3-methyl-2-butenal (2e) and isovaleraldehyde (2c).
- Tokuda,Mimura,Yoshioka,Karasawa,Fujita,Suginome
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- Dienyl homoallyl alcohols via palladium catalyzed ene-type reaction of aldehydes with 1,3-dienes
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The combination of Pd catalyst and Xantphos ligand in the presence of Et3B nicely promotes the allylation of aldehydes with conjugated dienes to provide dienyl homoallyl alcohols in excellent yields. The reaction occurs selectively at the C-C double bond bearing higher electron density.
- Fukushima, Masahiro,Takushima, Daiki,Kimura, Masanari
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supporting information; experimental part
p. 16346 - 16348
(2011/02/22)
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- Pd-catalyzed cross-coupling of allylsilane-vinylcopper species with aryl and vinyl halides: the first total synthesis of (-)-nomadone
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The reaction of allene with a lower order silylcuprate 3 leads to an allylsilane-vinylcopper intermediate 4, which undergoes palladium-catalyzed cross-coupling reaction with both vinyl and aryl halides. The influence of several factors such as the nature
- Pulido, Francisco J.,Barbero, Asunción,García, Carlos
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supporting information; experimental part
p. 5535 - 5540
(2009/12/04)
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- Transformation of carboxylic acid esters into 2-substituted allyl halides through tertiary cyclopropyl sulfonates. Application in the synthesis of (±)-ipsenol and (±)-ipsdienol, components of Ips typographus spark beetle pheromone
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Cyclopropanation of the ester group in ethyl 3-chloropropanoate and subsequent cleavage of the three-membered carbocycle in intermediate 1-(2-chloroethyl)cyclopropyl methanesulfonate gave 2-bromomethyl-4-chlorobut-1- ene, and the latter was used as key intermediate in the synthesis of racemic ipsenol and ipsdienol which are components of Ips typographus L. European spruce spark beetle pheromone. Pleiades Publishing, Inc., 2006.
- Matyushenkov,Kulinkovich
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p. 491 - 495
(2007/10/03)
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- A General Method for the Synthesis of 2-Alkyl Substituted 1,3-Dienes Starting from 2-(Chloromethyl)-3-tosylpropene
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The alkylation of the monolithium derivative 5 of 2-(chloromethyl)-3-tosylpropene (1) with bromo- or iodo-methyltrimethylsilane affords the β-silyl sulfone 7, which after nucleophilic substitution of the chlorine atom followed by β-elimination of tosyltrimethylsilane, promoted by tetrabutylammonium fluoride (TBAF), gives 2-substituted conjugated dienes 6 and the outer-ring diene 14.Racemic ipsenol (10b), an aggregation pheromone of the bark beetle Ips paraconfusus Lanier, is prepared.
- Najera, Carmen,Sansano, Jose Miguel
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p. 5829 - 5844
(2007/10/02)
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- 2-(Chloromethyl)-3-tosylpropene as useful reagent for the general synthesis of functionalized 2-substituted 1,3-dienes. Application to the synthesis of (±)-ipsenol
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The reaction of the monolithium derivative of 2-(chloromethyl)-3-tosylpropene (2) with bromomethyltrimethylsilane affords the β-silyl sulfone 7, which after nucleophilic substitution followed by fluoride induced β-elimination of tosyltrimethylsilane gives 2-substituted conjugated dienes 1. When compound 7 reacts first with zinc in the presence of isovaleraldehyde and then with tetrabutylammonium fluoride racemic ipsenol (10), an aggregation pheromone of the bark beetle Ips paraconfusus Lanier, is prepared.
- Najera,Sansano
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p. 3781 - 3784
(2007/10/02)
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- Narcissus trevithian and Narcissus geranium: Analysis and Synthesis of Compounds
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The essential oils of two narcissus varieties, Narcissus trevithian and Narcissus geranium, obtained by extraction of flowers followed by high vacuum distilation of the absolute, were analyzed by GC/MS.After separation in fractions, unknown compounds were isolated by preparative GLC and their structures established by NMR/IR spectroscopy.The synthesis of a number of new compounds, found for the first time in narcissus oil, is described.The two narcissus species are compared with respect to their main components and odor quality.All compounds found so far in narcissus varieties are listed.
- Dort, Hans M. van,Jaegers, Paul P.,Heide, Roel ter,Weerdt, Anton J. A. van der
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p. 2063 - 2075
(2007/10/02)
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- In Turn or in Reverse Palladium-Catalyzed Carbonyl Allylation and Diels-Alder Reaction by 2-Methylene-3-buten-1-ol
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Using PdCl2(PhCN)2-SnCl2, 2-methylene-3-buten-1-ol causes carbonyl allylation of various aldehydes to afford 1-substituted-3-methylene-4-penten-1-ols, the Diels-Alder reaction of those with dienophiles produces 1-(2-hydroxyethyl)cyclohexenes.Diels-Alder reaction of 2-methylene-3-buten-1-ol with dienophiles followed by carbonyl allylation produces isomeric 1-methylene-2-(hydroxymethyl)cyclohexanes.
- Masuyama, Yoshiro,Fuse, Manabu,Kurusu, Yasuhiko
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p. 1199 - 1202
(2007/10/02)
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- Intermediates useful for the chiral isoprenylation of aldehydes
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An improved process for preparing either optically pure enantiomer of the bark beetle pheromones ipsenol and ipsdienol is provided. The process is also applicable to the condensation of aldehydes of widely varying properties to the corresponding chiral alcohol. This invention also concerns novel intermediates R'2 B(2'-isoprenyl) wherein R' is isopinocampheyl, 2-isocaranyl and 4-isocaranyl.
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- The Organic Synthesis Using Haloboration Reaction 20. A Simple Synthesis of (2-Bromoallyl)diphenoxyborane by the Bromoboration of Allene and its Reaction with Carbonyl Compounds
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Bromoboration reaction of allene with boron tribromide, followed by the treatment with anisole gives (2-bromoallyl)diphenoxyborane which reacts with aldehydes and ketones to give 2-bromohomoallylic alcohols in excellent yields.
- Hara, Shoji,Suzuki, Akira
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p. 6749 - 6752
(2007/10/02)
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- ON THE DIRECT METALATION OF ISOPRENE
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Isoprene has been metalated in tetrahydrofuran with an excess of sterically hindered potassium dialkylamides, prepared by combining equimolar amounts of the corresponding lithium amide and potassium tert-butoxide.Subsequent reaction with oxirane, alkyl bromides, and pivaldehyde gave the expected coupling products in reasonable yields.Coupling with (CH3)2CHCH2CH=O and (CH3)2C=CHCH=O afforded the bark beetle pheromones (+/-)-ipsenol and (+/-)-ipsdienol in low yields.
- Klusener, P. A. A.,Tip, L.,Brandsma, L.
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p. 2041 - 2064
(2007/10/02)
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- Chiral synthesis VIA organoboranes. 26. An efficient synthesis of isoprenyl derivatives of borane - Valuable reagents for the isoprenylboration of aldehydes. A convenient route to both enantiomers of ipsenol and ipsdienol in high optical purity
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Preparation of B-isoprenyldialkylboranes is achieved by adopting the Brandsma modification of the Schlosser procedure, namely metallation of isoprene with potassium 2,2,5,5-tetramethylpiperidide followed by sequential treatment with 5-methoxydialkylborane and boron trifluoride-etherate. These reagents are used for the convenient isoprenylation of aldehydes. Reaction of isovaleraldehyde and β, β-dimethylacrolein with B2′isoprenyldiisopinocampheylborane provides both ipsenol and ipsdienol, respectively in 65% yields and 96% ee.
- Brown, Herbert C.,Randad, Ramnarayan S.
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p. 4463 - 4472
(2007/10/02)
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- A New Route to 1,3-Dienes using 3-Methylene-2,3-dihydrothiophene S,S-Dioxide as an Allyl Sulphone and Michael Acceptor: Synthesis of (+/-)-Ipsenol
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Substituted 2,5-dihidrothiophene S,S-dioxides, which are stable precursors of the corresponding buta-1,3-dienes, were prepared via reactions of 3-methylene-2,3-dihydrothiophene S,S-dioxide with electrophiles and nucleophiles; this method was appiled to the synthesis of (+/-)-ipsenol.
- Nomoto, Takashi,Takayama, Hiroaki
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p. 295 - 297
(2007/10/02)
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- Regiospecific Functionalization of Dimetalated Isopropenylacetylene, a Synthetic Equivalent of the Isoprene "Anion". An Efficient Synthesis of the Bark Beetle Pheromones (+/-)-Ipsenol and (+/-)-Ipsdienol
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Regiospecific (mono)functionalization of dilithiated isopropenylacetylene LiCCC(=CH2)CH2Li with a large number of electrophilic reagents ("E+")gave the compounds HCCC(=CH2)CH2E in high yields.Coupling with (CH3)2CHCH2CH=O and (CH3)2C=CHCH=O, followed by partial reduction of the triple bond with activated zinc powder, gave the bark beetle pheromones ipsenol and ipsdienol, respectively, in >55percent overall yields.
- Klusener, Peter A. A.,Kulik, Willem,Brandsma, Lambert
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p. 5261 - 5266
(2007/10/02)
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- CHEMISTRY OF THE ORGANOSILICON COMPOUNDS-165 2-TRIMETHYLSILYL-METHYL-1, 3-BUTADIENE-A VERSATILE BUILDING BLOCK FOR TERPENE SYNTHESIS
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Two types of synthetically useful reactions of 2-trimethylsilylmethyl-1,3-butadiene (7) are discussed.Reactions of 7 with acid chlorides, aldehydes, ketones and acetals activated by a Lewis acid give isoprenylated compounds, while 7 undergoes the Diels-Alder reaction whit dienophiles.High regiospecificity of the reaction qualifies 7 for a versatile building block of terpene synthesis.
- Sakurai, Hideki,Hosomi, Akira,Saito, Masaki,Sasaki, Koshi,Iguchi, Hirokazu,et al.
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p. 883 - 894
(2007/10/02)
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- DIMETHYLALUMINUM CHLORIDE CATALYZED ENE REACTIONS OF ALDEHYDES.
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Dimethylaluminum chloride, which is a mild Lewis acid and a proton scavenger, catalyzes the ene reactions of aliphatic and aromatic aldehydes with alkenes containing a disubstituted vinylic carbon. Proton-initiated rearrangements do not occur, since the alcohol-Lewis acid complex formed in the ene reaction reacts rapidly to give methane and a nonacidic aluminum alkoxide. Formaldehyde and excess Me//2AlCl give good yields of ene adducts with all types of alkenes. With 1 equiv of Me//2AlCl, formaldehyde and mono- and 1,2-disubstituted alkenes give gamma -chloro alcohols resulting from cis addition of chlorine and hydroxymethyl groups to the double bond. This work is pertinent to the synthesis of alcohols.
- Snider,Rodini,Kirk,Cordova
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p. 555 - 563
(2007/10/02)
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- α-SELENOCYCLOBUTYLLITHIUM AS A 2-LITHIO-1,3-DIENE EQUIVALENT. REGIOSELECTIVE (100 percent) SYNTHESIS OF IPSENOL
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1-substituted cyclobutenes and 2-substituted dienes are prepared in high yield and regioselectively from a variety of electrophiles and cyclobutanone via α-lithio-α-seleno-cyclobutyllithium.
- Halazy, S.,Krief, A.
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p. 1997 - 2000
(2007/10/02)
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- Diaklylaluminum chloride catalyzed ene reactions of aldehydes. Synthesis of ipsenol
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Dimethylaluminum chloride which is a mild Lewis acid and a proton scavenger, catalyzes the ene reactions of aliphatic and aromatic aldehydes. Proton initiated rearrangements do not occur, since the alcohol-Lewis acid complex formed in the ene reaction rapidly to give methane and a non-acidic aluminum alkoxide.
- Snider, Barry B.,Rodini, David J.
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p. 1815 - 1818
(2007/10/02)
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