- One-pot synthesis of 5-Alkylfuran-2(5H)-ones
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5-Alkylfuran-2(5H)-ones can be efficiently obtained using a one-pot approach, starting from methyl 3-nitropropanoate and aldehydes, in ethyl acetate, with Amberlyst A-21 as catalyst, in 60-90% overall yield. Copyright Taylor & Francis Group, LLC.
- Ma, Jie,Wang, Si Hong,Guan, Rong Tian
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Read Online
- Convenient synthesis of 5-alkylfuran-2(5H)-ones
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A convenient synthesis of 5-alkylfuran-2(5H)-ones are described starting from 3-nitropropanoate and aldehydes, promoted by neutral alumina, in 35-60% overall yields, via a condensation-lactonization-elimination pathway. Copyright
- Ma, Jie,Wang, Si Hong,Yin, Yan Bing
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Read Online
- Synthetic method γ - nonene lactone
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The invention relates to a synthesis method of γ - nonenolide, belongs to the technical field of perfume synthesis, first steps of adding malonic acid into a four-port flask containing a condensing tube and a water separator, adding piperidine, and then adding heptanal to the 95 - 105 °C condition to raise the temperature and react to obtain the intermediate 1. The second Acetic acid and hydrogen peroxide are mixed, the intermediate 1 is added dropwise, the control temperature is 40 °C, and the intermediate 2 is obtained. The third Intermediate 2, dichloromethane and triethylamine were mixed and acetyl chloride was added dropwise, and after the dropwise addition, γ - nonene lactone was obtained. No solvent is used in first steps of the invention, so that the reaction cost is reduced. The intermediate 1 is closed under the action of acetic acid and hydrogen peroxide, adopts hydrogen peroxide as an oxidant, and has the advantage of environmental friendliness. By replacing methane sulfonyl chloride with acetyl chloride, the use of methane sulfonyl chloride is reduced under the condition of ensuring the yield, the whole reaction process is simple, the route is short, and the raw materials are easily available.
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Paragraph 0019; 0023; 0024; 0028; 0029; 0033; 0038; 0039
(2021/11/10)
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- Large-Scale Synthesis of a Niche Olefin Metathesis Catalyst Bearing an Unsymmetrical N-Heterocyclic Carbene (NHC) Ligand and its Application in a Green Pharmaceutical Context
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A large-scale synthesis of known Ru olefin metathesis catalyst VII featuring an unsymmetrical N-heterocyclic carbene (NHC) ligand with one 2,5-diisopropylphenyl (DIPP) and one thiophenylmethylene N-substituent is reported. The optimised procedure does not require column chromatography in any step and allows for preparation of up to 0.5 kg batches of the catalyst from simple precursors. The application profile of the obtained catalyst was studied in environmentally friendly dimethyl carbonate (DMC). Although VII exhibited low efficiency in cross-metathesis (CM) with electron-deficient partners, good to excellent results were noted for substrates featuring easy to isomerise C?C double bonds. This includes polyfunctional substrates of medicinal chemistry interest, such as analogues of psychoactive 5F-PB-22 and NM-2201 and two PDE5 inhibitors—Sildenafil and Vardenafil. Finally, a larger scale ring-closing metathesis (RCM) of a Vardenafil derivative was conducted in DMC, allowing for straightforward isolation of the expected product (23 g) in high yield and with low Ru contamination level (7.7 ppm).
- Czajkowska-Szczykowska, Dorota,Czarnocki, Stefan,Grela, Karol,Kajetanowicz, Anna,Ma?ecki, Pawe?,Niena?towski, Tomasz,Paw?owska, Jolanta,Szczepanik, Pawe?
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supporting information
p. 15708 - 15717
(2020/12/01)
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- A facile synthesis of γ-butenolides via cyclization of 3-alkenoic acids with dimethyl sulfoxide and oxalyl bromide
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The combination of dimethyl sulfoxide and oxalyl bromide was used to accomplish the cyclization of 3-alkenoic acids with the aid of a base to afford γ-butenolides, in which bromodimethylsulfonium salt generated in situ was proposed to serve as a Br+ source.
- Ding, Rui,Liu, Yongguo,Liu, Lei,Li, Huimin,Tao, Sichen,Sun, Baoguo,Tian, Hongyu
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supporting information
p. 3001 - 3007
(2019/08/26)
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- Highly efficient and time economical purification of olefin metathesis products from metal residues using an isocyanide scavenger
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A sustainable protocol of olefin metathesis in non-degassed, undistilled ethyl acetate under air with commercially available self-scavenging ruthenium catalysts is described. Furthermore, a time economical, cost-effective and scalable method of removal of ruthenium residues is presented. Treatment of post-reaction mixtures with an isocyanide scavenger and then with acid followed by a simple filtration is shown to yield OM products with ruthenium contamination below 5 ppm even in highly challenging cases. Finally, a telescope RCM/Suzuki-Miyaura sequence with a rapid and efficient purification protocol for simultaneous removal of Ru and Pd residues from solution is described.
- Szczepaniak, Grzegorz,Ruszczyńska, Anna,Kosiński, Krzysztof,Bulska, Ewa,Grela, Karol
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supporting information
p. 1280 - 1289
(2018/03/28)
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- Preparation method of alpha, beta-unsaturated-gamma-lactone
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The invention relates to a preparation method of alpha, beta-unsaturated-gamma-lactone shown as a structural formula below. The preparation method comprises the following steps: firstly dropwise adding a dichloromethane solution of dimethylsulfoxide (1.5 equiv) into a dichloromethane solution of oxaloyl bromide (1.5 equiv) at a temperature of 10 DEG C below zero, dropwise adding raw material (E) 3-alkenoic acid, then returning to a room temperature for reaction, adding a potassium carbonate aqueous solution and continuously reacting to obtain the corresponding alpha, beta-unsaturated-gamma-lactone; the yield is 85-90 percent.
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Paragraph 0005; 0016; 0017
(2018/09/08)
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- A Novel Method for the Chlorolactonization of Alkenoic Acids Using Diphenyl Sulfoxide/Oxalyl Chloride
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A facile chlorolactonization of alkenoic acids by treatment with diphenyl sulfoxide/oxalyl chloride has been developed. The reaction can generate various chlorolactones in moderate to good yields, wherein the chlorodiphenylsufonium salt derived from diphenyl sulfoxide/oxalyl chloride serves as the source of Cl +.
- Ding, Rui,Lan, Liyuan,Li, Shuhui,Liu, Yongguo,Yang, Shaoxiang,Tian, Hongyu,Sun, Baoguo
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p. 2555 - 2566
(2018/05/03)
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- Method for preparing alpha,beta-unsaturated gamma-lactone
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The invention relates to a method for preparing alpha,beta-unsaturated gamma-lactone represented by structural formula shown in the description. The method comprises the following steps: dropwise adding a dichloromethane solution of diphenyl sulfoxide (1.5 eq) to a dichloromethane solution of oxalyl chloride (1.5 eq) (or oxalyl bromide (1.5 eq)) at -78 DEG C, dropwise adding a raw material (E)-3-alkenoic acid, adding potassium carbonate and 18-crown-6 ether, and carrying out room temperature reaction to obtain the corresponding alpha,beta-unsaturated gamma-lactone with the yield of 80-85%.
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Paragraph 0012-0013; 0016-0017
(2018/01/09)
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- Organocatalytic sequential α-aminoxylation and cis-Wittig olefination of aldehydes: Synthesis of enantiopure γ-butenolides
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A short route to enantiopure γ-butenolides (up to 99% ee) has been developed from readily available starting materials. The strategy involves a sequential organocatalytic α-aminoxylation followed by cis-Wittig olefination of aldehydes. The utility of this protocol has been demonstrated in the asymmetric synthesis of trans-(+)-cognac lactone with high enantiomeric purity.
- Devalankar, Dattatray A.,Chouthaiwale, Pandurang V.,Sudalai, Arumugam
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experimental part
p. 240 - 244
(2012/06/04)
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- Efficient synthesis of the odourant, 2-nonen-4-olide
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A three-step synthesis of 2-nonen-4-olide starting from heptanal is reported. (E)-3-Nonenoic acid, prepared by Knoevenagel condensation of malonic acid and heptanal, was oxidised by performic acid, a process accompanied by lactonisation, to give 3-hydroxynonan-4-olide in 85% yield. This lactone when reacted with MsCl in the presence of Et3N gave, by elimination, 2-nonen-4-olide in 88% yield. The overall yield was 75%. The odour of the product was evaluated by GC-olfactory analysis and sniffing blotter confirming an oily, coconut-like, and rancid odour.
- Dai, Yi-Feng,Tian, Hong-Yu,Sun, Bao-Guo,Sun, Yu-Mei,Chen, Hai-Tao,Liu, Xiao-Yu
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p. 495 - 496
(2012/10/29)
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- Organo-catalyzed enantioselective synthesis of some β-silyl γ-alkyl γ-butyrolactones as intermediates for natural products
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The enantioselective synthesis of some β-silyl γ-alkyl γ-butyrolactones has been achieved by an organo-catalyzed Michael addition of enolizable aldehydes onto a silylmethylene malonate followed by a silicon-facilitated Bayer-Villiger oxidation of the β-silyl aldehyde adducts as the key step. γ-Alkyl γ-butenolides were obtained from the β-silyl γ-alkyl γ-butyrolactones by Fleming-Tamao oxidation of the silyl group to a hydroxy group and subsequent elimination. These butenolides are the advanced intermediates of some natural products such as (+)-γ-caprolactone, (+)-methylenolactocine, and (-)-quercus lactone.
- Chowdhury, Raghunath,Ghosh, Sunil K.
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experimental part
p. 1895 - 1900
(2012/01/05)
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- Catalytic enantioselective synthesis of naturally occurring butenolides via hetero -allylic alkylation and ring closing metathesis
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An efficient catalytic asymmetric synthesis of chiral γ-butenolides was developed based on the hetero-allylic asymmetric alkylation (h-AAA) in combination with ring closing metathesis (RCM). The synthetic potential of the h-AAA-RCM protocol was illustrated with the facile synthesis of (-)-whiskey lactone, (-)-cognac lactone, (-)-nephrosteranic acid, and (-)-roccellaric acid.(Figure Presented)
- Mao, Bin,Geurts, Koen,Fananas-Mastral, Martin,Van Zijl, Anthoni W.,Fletcher, Stephen P.,Minnaard, Adriaan J.,Feringa, Ben L.
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supporting information; experimental part
p. 948 - 951
(2011/04/23)
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- Catalytic use of selenium electrophiles in cyclizations
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A new and convenient one-pot method for a catalytic addition-elimination reaction using selenium electrophiles has been developed. In the presence of 5 mol % diphenyl diselenide, [bis(trifluoroacetoxy)iodo]benzene in acetonitrile converted a range of (E)-3-butenoic acids into the corresponding butenolides in good yields.
- Browne, Danielle M.,Niyomura, Osamu,Wirth, Thomas
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p. 3169 - 3172
(2008/02/10)
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- Enantioselective butenolide preparation for straightforward asymmetric syntheses of γ-lactones - Paraconic acids, avenaciolide, and hydroxylated eleutherol
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The naturally occurring γ-lactones (+)-methylenolactocin (13) and its enantiomer, (+)-protolichesterinic acid (14) and its enantiomer, (+)-rocellaric acid (15), and the methylene bis(γ-lactone) (-)-avenaciolide (16) were synthesized with 95-98 % ees in very few steps. Enantiocontrol was imposed by the asymmetric dihydroxylation of trans-configured β,γ-unsaturated carboxylic esters (namely compounds 1i, 1j, and 1n) with AD mix-α [for the levorotatory target structures, except for (-)-avenaciolide] or AD mix-β [for the dextrorotatory target structures plus (-)-avenaciolide]. β,γ-Unsaturated carboxylic ester 1e required increased amounts of the oxidant and auxiliary to produce the hydroxy lactone R,R-3e, a precursor of the naphtho-γ-lactone (+)-9-hydroxyeleutherol (12; 96 % ee). Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Braukmueller, Stefan,Brueckner, Reinhard
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p. 2110 - 2118
(2007/10/03)
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- Synthesis of α,β-unsaturated γ-lactones via photooxygenation of 2,3-dihydrofurans followed by ferrous ion-catalyzed gem-dehydration
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Several alkyl and aryl substituted 2,3-dihydrofurans 1a-1e were synthesized and their reactions with singlet oxygen were investigated. Photooxygenation of 1a-1e in carbon tetrachloride at ambient temperature exclusively yields allylic hydroperoxides 4a-4e. Treatment of these hydroperoxides with aqueous ferrous sulfate solution affords the corresponding α,β-unsaturated γ-lactones 6a-6e with high yields. This work provides an efficient route to the preparation of butenolide moiety, an important functionality in the structures of many natural products that exhibit biological properties.
- Chen, Yu-Zhe,Wu, Li-Zhu,Peng, Ming-Li,Zhang, Dong,Zhang, Li-Ping,Tung, Chen-Ho
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p. 10688 - 10693
(2007/10/03)
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- Enantioselective syntheses and configuration assignments of γ-chiral butenolides from Plagiomnium undulatum: Butenolide synthesis from tetronic acids
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Both enantiomers of the γ-chiral α,β-dimethylated butyrolactones nat-1 and nat-2 from the moss Plagiomnium undulatum were synthesized stereoselectively through butenolides and tetronic acids, respectively. The configuration of the natural products was determined by GLC comparisons with mono(3-O-acetyl-6-O-tert-butyldimethylsilyl-2-O-methyl) hexakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin as a stationary phase.
- Kapferer, Tobias,Brueckner, Reinhard,Herzig, Axel,Koenig, Wilfried A.
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p. 2154 - 2162
(2007/10/03)
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- The β-lactone route to β-hydroxy or α,β-unsaturated γ- and δ-lactones. Syntheses of (±)-Massoialactone and (±)-Prelactone B
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Aqueous HF promotes the translactonization of silyloxy β-lactones into β-hydroxy or α,β-unsaturated γ- and δ-lactones. The reaction is studied from a theoretical point of view and applied to the racemic synthesis of two natural bioactive δ-lactones.
- Fournier, Lycia,Gaudel-Siri, Anouk,Kocieński, Philip J.,Pons, Jean-Marc
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p. 107 - 111
(2007/10/03)
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- A convergent asymmetric synthesis of γ-butenolides
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The addition of aldehydes to the new enantiomerically pure lithiated sulfoxide-orthoester 13 yielded γ-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The cyclocondensation with ketones was less stereoselective. This new asymmetric synthesis of γ-butenolides has been applied to a convergent preparation of the antifungal antibiotic (+)-cerulenin.
- Renard, Marc,Ghosez, Léon A.
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p. 2597 - 2608
(2007/10/03)
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- Ruthenium carbene complexes with N,N'-bis(mesityl)imidazol-2-ylidene ligands: RCM catalysts of extended scope
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The ruthenium carbene complexes 3a,b bearing imidazol-2-ylidene ligands constitute excellent precatalysts for ring-closing metathesis (RCM) reactions allowing the formation of tri- and tetrasubstituted cycloalkenes. They also apply to annulations that are beyond the scope of the standard Grubbs carbene 1 as well as to ring-closing reactions of acrylic acid derivatives even if the resulting α,β-unsaturated lactones (or lactams) are tri- or tetrasubstituted. The reactivity of 3a was found to be highly dependent on the reaction medium: particularly high reaction rates are observed in toluene, although this solvent also leads to an increased tendency of the catalyst to isomerize the double bonds of the substrates.
- Fuerstner, Alois,Thiel, Oliver R.,Ackermann, Lutz,Schanz, Hans-Joerg,Nolan, Steven P.
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p. 2204 - 2207
(2007/10/03)
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- A convergent asymmetric synthesis of γ-butenolides
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Addition of aldehydes to the new enantiomerically pure lithiated sulfoxide 4 yielded γ-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The reaction with ketones was less stereoselective.
- Renard, Marc,Ghosez, Leon
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p. 6237 - 6240
(2007/10/03)
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- Photooxygenation of chiral dienol ethers: Asymmetric synthesis of alkoxydioxines
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The addition of 1O2 to chiral dienol ethers provides a new route to alkoxydioxines (alkoxyendoperoxides). Depending upon substitution and geometry, the [4+2] cycloaddition is accompanied or even supplanted by [2+2] cycloaddition leading to alkene cleavage and/or ene-like reaction leading to allylic hydroperoxides. The diastereoselectivity of cycloaddition is ultimately limited by the conformational freedom of the dienol ether substrates.
- Dussault, Patrick H.,Han, Qiang,Sloss, Darby G.,Symonsbergen, David J.
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p. 11437 - 11454
(2007/10/03)
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- Enantioselective hydrogenation of β-keto sulfones with chiral Ru(II)- catalysts: Synthesis of enantiomerically pure butenolides and γ- butyrolactones
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A series of β-hydroxy sulfones were synthesized with high enantioselectivities via a new enantioselective ruthenium-catalyzed hydrogenation using MeO-BIPHEP as a ligand. Some β-hydroxy sulfones were used in the synthesis of optically active butenolides and γ-butyrolactones with high yields and enantioselectivities over 95%.
- Bertus,Phansavath,Ratovelomanana-Vidal,Genet,Touati,Homri,Hassine, B. Ben
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p. 1369 - 1380
(2007/10/03)
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- Synthetic Routes to Allenic Acids and Esters and Their Stereospecific Conversion to Butenolides
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The synthesis of allenic acids and esters and their conversion to butenolides has been examined in some detail. Racemic butenolides 10 are efficiently prepared from the esters 8 through treatment with BCl3 and exposure of the derived acid 9 to catalytic AgNO3 in acetone. Conversion of the enantioenriched allenylstannane (S)-17 to the acid 18 through lithiation and subsequent carboxylation with CO2 afforded racemic product. The enantioenriched propargylic mesylates 16 and 22 afforded the allenic esters 19 and 23 with inversion of configuration through treatment with Pd(Ph3P)4, CO, and the appropriate alcohol in THF. These reactions proceeded with ca. 10% or less of racemization. The allenic esters 23 yielded the iodobutenolides 24 by reaction with IBr. Hydrogenolysis to the butenolide 25 was achieved with Pd(PPh3)4 and Bu3SnH. Alternatively, the allenic acids 27 could be prepared directly from mesylates 22 with Pd(PPh3)4 and CO in aqueous THF. Cyclization to the butenolides 25 was achieved, as before, with catalytic AgNO3.
- Marshall, James A.,Wolf, Mark A.,Wallace, Eli M.
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p. 367 - 371
(2007/10/03)
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- Concise syntheses of natural γ-butyrolactones, (+)-trans-whisky lactone, (+)-trans-cognac lactone, (-)-methylenolactocin, (+)-nephrosteranic acid, and (+)-roccellaric acid using novel chiral butenolide synthons
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cis-4-Hydroxy-5-(iodomethyl)-4,5-dihydro-2(3H)-furanones (1 and ent-1) were converted by cross-coupling with several Grignard-derived cuprates followed by benzoylation and base-induced elimination into new chiral butenolides 12, 14, ent-14, 20, and 27. The sequential conjugate addition - quenching of these butenolides under complete stereocontrol provided several polysubstituted γ-butyrolactones including flavor components [(±)-trans-whisky lactone (3) and (+)-trans-cognac lactone (4)], the antitumor antibiotic lactone (-)-methylenolactocin (5), and lichen components [(+)-nephrosteranic acid (7) and (+)-roccellaric acid (8)].
- Takahata,Uchida,Momose
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p. 5628 - 5633
(2007/10/03)
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- Lithiated 3-Tosylpropanal and 4-Tosyl-2-butanone Dimethyl Acetals as β-Acylvinyl Anion Equivalents for the Synthesis of Unsaturated 1,4-Dicarbonyl Compound and α,β-Butenolides
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The lithiation of 1,1-dimethoxy-3-tosyllpropane (7a) and 2,2-dimethoxy-4-tosylbutane (7b) followed by reaction with acyl chlorides affords, after p-toluenesulfinic acid elimination, ene-1,4-dicarbonyl compounds in a stereoselective manner.In the case of compound 7a, derived from acrolein, sequential monolithiation and reaction with carbonyl compounds give cyclic acetals, which after oxidation and elimination of p-toluenesulfinic acid are transformed into α,β-butenolides.
- Bonete, Pedro,Najera, Carmen
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p. 2763 - 2776
(2007/10/02)
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- New Entry to Chiral Butenolide Synthons. Application to Expeditious Syntheses of (+)-Nephrosteranic Acid, (+)-trans-Whisky Lactone, and (+)-trans-Cognac Lactone
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A new entry to chiral butenolide synthons starting with iodolactonization of the readily available, homochiral N-benzyl-N-methyl-3-hydroxy-4-pentenamide (1) and its application to the syntheses of (+)-nephrosteranic acid (5), (+)-trans-whisky lactone (6), and (+)-trans-cognac lactone (7) are described.
- Takahata, Hiroki,Ushida, Yasuhiro,Momose, Takefumi
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p. 4123 - 4124
(2007/10/02)
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- Lithium 3-Lithio-3-tosylalkanoates: β-Acylvinyl Anion Equivalents of β-Lithiated α,β-Unsaturated Carboxylic Acids
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The dilithiation of β-tosylated propanoic, 2-methylpropanoic, and butanoic acid 10 with n-butyllithium at -78 deg C leads to the corresponding lithium 3-lithio-3-tosylalkanoates 11.They react with different electrophilic reagents (deuterium oxide, iodine, trimethylchlorosilane, alkyl halides, and acyl chlorides) to give the corresponding 3-substituted tosylated alkanoic acids 12.When carbonyl compounds are allowed to react with intermediates 11 followed by in situ lactonization with trifluoroacetic anhydride and base-promoted elimination α,β-butenolides are obtained.This methodology is applied to the direct synthesis of the rosefuran lactone precursor 14cg, the O-benzyl derivative of (+/-)-umbelactone (14ch), and (+/-)-andirolactone (14ci).The alkylation and acylation reactions of organolithium compounds 11 followed by esterification with hydrogen chloride in methanol and treatment with 1,8-diazabicycloundec-7-ene (DBU) afford α,β- and/or β,γ-unsaturated esters 17 and/or 18 and unsaturated 4-keto esters 19, respectively.The last methodology has been applied to the synthesis of the unsaturated 4-keto ester 19ae precursor of the seco acid of (+/-)-pyrenophorin (22).
- Bonete, Pedro,Najera, Carmen
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p. 3202 - 3209
(2007/10/02)
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- Oxidative deselenylation with sodium perborate and sodium percarbonate
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In the presence of acetic anhydride, both sodium perborate and sodium percarbonate have been found to be effective reagents for the oxidation of α-phenylselenocarbonyl compounds to α,β-unsaturated carbonyl compounds.
- Kabalka,Reddy,Narayana
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p. 543 - 548
(2007/10/02)
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- Lithium 3-lithio-3-tosylpropanoate: A useful α-tosylated homoenolate anion
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Lithium 3-lithio-3-tosylpropanoate prepared by dilithiation of 3-tosylpropanoic acid with n-butyllithium at -78°C, reacts with different electrophiles yielding the expected 3-functionalized tosylated propanoic acids. When carbonyl compounds are used as electrophiles the corresponding α,β-butenolides are prepared directly.
- Bonete,Najera
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p. 4065 - 4068
(2007/10/02)
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- Synthesis of optically active α-trimethylsilyl Δ(α,β)-butenolides and their conversion into various butenolides and saturated γ-lactones
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Highly efficient method for synthesis of enantiomerically pure α,β-unsaturated butenolides having trimethylsilyl group at α-position (1) and their conversion into various butenolides and saturated γ-lactones are described.
- Ito,Okamoto,Sato
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p. 6399 - 6402
(2007/10/02)
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- Synthesis of cis and trans Whisky and Cognac Lactones by the Regiocontrolled Alkylation of 2-(Trimethylsiloxy)furan
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The racemic cis- and trans-5-butyltetrahydro-4-methylfuran-2-ones ( = whisky lactones) and their higher homologues tetrahydro-4-methyl-5-pentylfuran-2-ones ( = cognac lactones) have been prepared in 2-3 steps from 2(trimethylsiloxy)furan.Regioselective alkylation of the latter afforded the 5-butyl- and 5-pentylfuran-2(5H)-ones which served as precursors for the stereocontrolled construction of either diastereoisomer of the beverage lactones.The structure and tautomerization of the diazomethane adducts of these 5-alkylfuran-2(5H)-ones are also described.
- Jefford, Charles W.,Sledeski, Adam W.,Boukouvalas, John
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p. 1362 - 1370
(2007/10/02)
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- Regioselective Alkylation of 2-Trimethylsiloxyfuran; Direct Access to 4-Substituted But-2-en-4-olides
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Primary iodides alkylate 2-trimethylsiloxyfuran in the presence of a molar excess of silver trifluoroacetate to give the 4-alkylbut-2-en-4-olides in 55-81percent yield; as an illustration of the method, the cytotoxic marine sponge constituent, 4-(methoxycarbonylmethyl)but-2-en-4-olide was prepared in 79percent yield in one step.
- Jefford, Charles W.,Sledeski, Adam W.,Boukouvalas, John
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p. 364 - 365
(2007/10/02)
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- SYNTHESIS OF 5-ALKYL-3H-THIOLEN-2-ONES AND 5-ALKYL-3H-FURAN-2-ONES AND CONDENSATION REACTIONS AT THE HETEROCYCLIC METHYLENE GROUP
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The intramolecular cyclization of γ-ketocarboxylic acids and their esters gives 5-alkylsubstituted 3H-thiolen-2-ones and 3H-furan-2-ones.It was shown that reaction occured at the heterocyclic methylene group and that the conditions under which the reaction took place depended on the nature of the heterocyclic atom.
- Sedavkina, V. A.,Morozova, N. A.,Egorova, A. Yu.,Ostroumov, I. G.
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p. 377 - 380
(2007/10/02)
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- A Facile and General Entry to Optically Active Pheromones and Aromas With γ-Alkyl-γ-lactone Structures. A Study of Some Lactone Derivatives of Pentoses
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A new and easy general methodology has been developed to prepare γ-alkyl-α,β-butenolides or γ-alkylbutyrolactones in four and five steps, respectively, from D-ribonolactone as a common chiral starting material.Some of these products have pheromonal activity in insects and are also used as fruit fragrances.A study on several derivatives of D-ribonolactone and 2-deoxy-D-ribonolactone has been carried out in order to explore alternative routes for these syntheses.
- Cardellach, J.,Font, J.,Ortuno, R. M.
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p. 327 - 331
(2007/10/02)
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- DIANIONS OF N-MONOSUBSTITUTED-3-(PHENYLSULFONYL)PROPANAMIDES. CONVENIENT REAGENTS FOR THE SYNTHESIS OF 5-ALKYL-2(5H)-FURANONES
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Treatment of N-phenyl-3-(phenylsulfonyl)propanamide with 2 equiv. of butyllithium at -78 deg C afforded the dianion.Aldehydes and ketones upon treatment with the dianion provided stable γ-hydroxy amides, which were converted in good yields to 5-alkyl-2(5H)-furanones.Optically active (R)- and (S)-5-octyl-2(5H)-furanones, and (R)- and (S)-5-tridecyl-2(5H)-furanones were prepared from aldehydes and the dianions, derived from chiral N-monosubstituted-3-(phenylsulfonyl)propanamides.
- Tanaka, Kazuhiko,Wakita, Hisanori,Yoda, Hidemi,Kaji, Aritsune
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p. 1359 - 1362
(2007/10/02)
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- SELECTIVE REACTIONS OF THIOLATE ANIONS WITH 4-HYDROXY-E-2-ALKENOIC ESTERS OR 4-METHANESULFONYLOXY-E-2-ALKENOIC ESTERS. SYNTHESIS OF 2-ALKEN-4-OLIDES (Δα,β-BUTENOLIDES) AND E,E-2,4-ALKADIENOIC ESTERS
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Methyl 4-hydroxy-E-2-alkenoates prepared from aldehydes in one step, undergo the Michael reactions with thiolate anions to give 4-alkanolide derivatives, which are converted into 2-alken-4-olides.Methyl 4-methanesulfonyloxy-E-2-alkenoates undergo the substitution reactions, and subsequent treatments give methyl E,E-2,4-alkadienoates.
- Tanikaga, Rikuhei,Nozaki, Yoshihito,Tanaka, Kazuhiko,Kaji, Aritsune
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p. 1703 - 1706
(2007/10/02)
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- SYNTHESE DE Δ-2 BUTENOLIDES A PARTIR DU FURFURAL
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The reaction of two molecular equivalents of organolithium derivatives with 4-hydroxy-2-butenolide (easily prepared from furfural) leads to 4-substituted butenolides with excellent yields.
- Machado-Araujo, F.Welbaneide,Gore, Jacques
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p. 1969 - 1972
(2007/10/02)
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