- Method for synthesizing terminal alkyne by utilizing 1, 2-dihaloalkane
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The invention discloses a method for synthesizing terminal alkyne by utilizing 1, 2-dihaloalkane. According to the method, 1, 3-dihaloalkane is used as a raw material and terminal alkyne is synthesized under the action of alkali and a catalyst, wherein the molar ratio of the alkali to the 1, 2-dihaloalkane is 2: 1-5: 1, the use amount of the catalyst is 2%-10% of the mass of the 1, 2-dihaloalkane,the reaction temperature is 100-150 DEG C and the reaction time is 3-10 h. The method has the advantages of environmental protection, high selectivity, high yield and the like.
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Paragraph 0025-0027
(2020/04/29)
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- Preparation method of methyl dihydrojasmonate
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The invention discloses an efficient synthesis method of methyl dihydrojasmonate. Under catalysis of homogeneous rhodium and organic nitric oxide, 1-heptyne and ethylene have Pauson-Khand reaction, 2-amyl-2-cyclopentenone is rapidly and efficiently obtained, and an intermediate is subjected to addition and decarboxylation by dimethyl malonate to obtain the methyl dihydrojasmonate. The efficient synthesis method mainly has the advantages that 1-heptyne and ethylene Pauson-Khand reaction yield is effectively improved by the aid of the organic nitric oxide, and usage of rhodium catalysts is reduced. Compared with a traditional methyl dihydrojasmonate production method, the method has the advantages that route steps are short, atom economy is high, the cost is low, and the method is suitable for scale production of the methyl dihydrojasmonate.
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Paragraph 0026; 0053; 0054
(2018/05/01)
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- Control of the Regioselectivity in Cobalt- versus Ruthenium-Catalyzed Alder-ene Reaction of Unsymmetrical 1,3-Diynes
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The Alder-ene reaction of trialkylsilyl-substituted 1,3-butadiynes with terminal alkenes was investigated utilizing a cobalt-based catalyst, and the results were compared with Alder-ene rections catalyzed by the [CpRu(H3CCN)3]PF6 catalyst. Obviously, the two catalysts gave complementary results of yn-dienes differing in the site where the new carbon-carbon bond was formed. Of particular interest are observations concerning the double bond migration within the alkene component. While simple alkenes gave exclusively the E-configuration, the application of 3-buten-1-ol resulted in the corresponding Z-double bond, indicating that the hydroxyl group acts as donor coordinating to the cobalt center and thereby altering the reaction pathway.
- Weber, Sebastian M.,Hilt, Gerhard
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supporting information
p. 564 - 567
(2017/02/10)
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- Aerobic oxynitration of alkynes with tBuONO and TEMPO
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An efficient method for stereoselective nitroaminoxylation of alkyne has been reported. The reaction enjoys a broad substrate scope, good functional group tolerance, and high yields. Synthetically useful α-nitroketones can be accessed through these products in a single step.
- Dutta, Uttam,Maity, Soham,Kancherla, Rajesh,Maiti, Debabrata
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supporting information
p. 6302 - 6305
(2015/02/19)
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- Copper-catalyzed cross-coupling of alkyl and aryl grignard reagents with alkynyl halides
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(Chemical Equation Presented) Good old copperl A new general procedure to couple aliphatic and aromatic Grignard reagents with alkynyl halides under copper catalysis is described (see scheme; NMP=N-methylpyrrolidinone). The reaction is chemoselective and allows preparation of a vast array of simple and functionalized internal alkynes in high yields.
- Cahiez, Gerard,Gager, Olivier,Buendia, Julien
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supporting information; experimental part
p. 1278 - 1281
(2010/05/18)
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- Thieme Chemistry Journal Awardees - Where are they now? A general one-step synthesis of alkynes from enolisable carbonyl compounds
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Terminal and internal acetylenes were obtained in good to excellent isolated yields from carbonyl compounds by converting the carbonyl functionality into the enol nonaflate intermediate followed by elimination to give the C-C triple bond. The one-pot transformations were uniformly induced by phosphazene bases combined with mildly electrophilic nonafluorobutane-1-sulfonyl fluoride. The method is the most general among those reported to date as it applies to both acyclic ketones and aldehydes. Only moderate kinetic regioselectivity in favour of alk-1-yne achieved from methyl n-alkyl ketone represents a limitation of the method. In all the other instances, individual acetylenic products were obtained. Georg Thieme Verlag Stuttgart.
- Lyapkalo, Ilya M.,Vogel, Michael A. K.,Boltukhina, Ekaterina V.,Vav?ík, Ji?í
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scheme or table
p. 558 - 561
(2009/07/09)
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- Highly efficient photochemical generation of a triple bond: Synthesis, properties, and photodecarbonylation of cyclopropenones
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UV irradiation of alkyl-, aryl-, and heteroatom-substituted cyclopropenones results in the loss of carbon monoxide and the formation of quantitative yields of corresponding alkynes. The quantum yield of the photochemical decarbonylation reaction ranges from 20% to 30% for alkyl-substituted cyclopropenones to above 70% for the diphenyl- and dinaphthylcyclorpopenones. Rapid formation (5 ns) and then a somewhat slower decay (ca. 40 ns) of an intermediate in this reaction was observed by using laser flash photolysis. The DFT calculations allowed us to identify this intermediate as a zwitterionic species formed by a cleavage of one of the carbon-carbon bonds of the cyclopropenone ring. The latter then rapidly loses carbon monoxide to produce the ultimate acetylenic product. Despite their high photoreactivity, cyclopropenones were found to be thermally stable compounds with the exception of hydroxy- and methoxy-substituted cyclopropenones. The latter undergo rapid solvolysis in hydroxylic solvents even at room temperature. The application of this reaction to the in situ generation of the enediyne strucutre was illustrated by the photochemical preparation of benzannulated enediyne 12.
- Poloukhtine, Andrei,Popik, Vladimir V.
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p. 7833 - 7840
(2007/10/03)
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- Synthesis, characterisation and reactivity of 2-functionalised vinylstannanes
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The functionalised vinylstannanes of the type (E)/(Z)-Ph3SnCR′=CHYRn and (E)/(Z)-Ph3SnC(YRn)=CHR′ (YRn=NMe2, OEt, SMe, SEt; R′=Ph, Bu (n-butyl), Pe (n-pentyl), H) were prepared by non-catal
- Lébl,Hole?ek,Dymák,Steinborn
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- A Novel Transformation of Esters to Alkynes with 1-Substituted Benzotriazoles
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Reactions of lithio benzotriazol-1-yl derivatives 2, 11, and 25 with aromatic and aliphatic esters 3, 12, and 26 gave α-(benzotriazol-l-yl) ketones 4, 13, and 27, respectively, in high yields. Alternatively, α-(benzotriazol-l-yl) ketones 22 can be accessed by the reaction of α-(benzotriazol-1-yl) esters 20 with Grignard reagents. Condensation of 4, 13, 22, and 27 with (p-toluenesulfonyl)hydrazine provided p-tosylhydrazones 5, 14, 21, and 28. Treatment of hydrazones 5, 21, and 28 with n-butyllithium in diethyl ether resulted in the elimination of the tosyl group, dinitrogen, and benzotriazolyl group to afford the corresponding acetylenes 9, 23, and 29 in good yields. When α-(benzotriazol-l-yl) 1-α-phenoxy hydrazones 14 were treated with methyllithium, n-butyllithium, or phenyllithium, alkynes 18 were obtained, in which phenoxy groups were replaced by the lithium reagents.
- Katritzky, Alan R.,Wang, Jin,Karodia, Nazira,Li, Jianqing
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p. 4142 - 4147
(2007/10/03)
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- Synthesis and Nuclear Magnetic Resonance Studies on a Series of Synthesis Long-chain Tellurophene Fatty Esters
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The synthesis and the results of the 1H and 13C NMR spectroscopic analyses of thirteen 2,5-disubstituted tellurophene fatty esters, containing substituents of different chain lengths, and of a monosubstituted tellurophene ester are repported.The tellurophene esters are obtained by cyclization of the corresponding conjugated intermediates with Na2Te in the presence of AgOAc in methanol.The tellurophene moiety in the alkyl chain induces a deshielding effect on the protons of the adjacent methylene prtons.The shift parameters of the tellurophene moiety on the shifts of the adjacent methylene carbon atoms are also determined.
- Jie, Marcel S. F. Lie Ken,Chau, Sherman H.
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p. 2642 - 2657
(2007/10/03)
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- Conversion of Allyl Alk-2-ynoates to Alk-2-ynoic Acids Using Morpholine and Palladium(0)-Bis(diphenylphosphino)alkane Catalyst; Synthesis of 2,2,3,3-Tetradehydro PGE1
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Allyl alk-2-ynoates can be readily converted into alk-2-ynoic acids by the reaction with morpholine in the presence of a palladium-diphenylphosphinopropane catalyst, thus providing the chemical deprotection method of allyl ester of 2,2,3,3-tetradehydro PGE1.
- Okamoto, Sentaro,Ono, Naoya,Tani, Kousuke,Yoshida, Yukio,Sato, Fumie
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p. 279 - 280
(2007/10/02)
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- Studies on the Thermal Conversion of Long-chain Alkynes at High Temperatures in the Gas Phase
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In the gas phase pyrolysis of long-chain alkynes C5 to C9 at 773 to 873 K, a remarkable portion of molecular reaction (retro-ene analogous decompositions as well as cycloisomerizations of the parent alkynes to cyclopentenes alkylated in 3-position) takes place besides the thermal conversion of the starting compounds via radical chain processes.The different products were separated by GC and the main products identified by means of different methods.The mechanisms of formation of the major products are discussed.
- Ondruschka, B.,Zimmermann, G.,Ziegler, U.,Kopinke, F.-D.,Teuber, M.
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p. 273 - 284
(2007/10/02)
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- DIOLS AS EFFECTIVE COCATALYSTS IN THE PHASE TRANSFER CATALYZED PREPARATION OF 1-ALKYNES FROM 1,2-DIHALIDES
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Bis-tertiary diols accelerate bis-eliminations of HX from 1,2-dihalides in the presence of an onium salt as phase transfer catalyst and potassium hydroxyde as base.PEG 400 catalyzes the same elimination, but isomerizations from 1-alkyne to mixtures with the 2-alkyne and the 1,2-diene occur easily.
- Dehmlow, Eckehard V.,Thieser, Rainer,Sasson, Yoel,Neumann, Ronny
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p. 3569 - 3574
(2007/10/02)
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- Selective Synthesis of Alkynes by Catalytic Dehydrogenation of Alkenes over Polymer-supported Palladium Acetate in the Liquid Phase
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A heterogenized palladium acetate catalyst, in the presence of oxygen and perchloric acid in ethanol-water caused the direct conversion of terminal and internal monoalkenes into the corresponding alkynes, under mild conditions and in high yields; Wacker-type ketonization occurs with the same reagents in dioxane-water.
- Cum, Giampietro,Gallo, Raffaele,Ipsale, Salvatore,Spadaro, Agatino
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p. 1571 - 1573
(2007/10/02)
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- Application of Phase Transfer Catalysis, 14.- Preparation of Alkynes from Halides with Solid Potassium tert-Butoxide and Crown Ether
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Preparatively very simple and mild HX eliminations with solid potassium tert-butoxide in petroleum ether in the presence of catalytic amounts of crown-6 are described. 1,2-Dihalides (from alkenes) and 1,1-dihalides (from aldehydes) yield 1-alkynes; internal geminal dihalides (from symmetric ketones) give internal alkynes in excellent yields. 2,2-Dihalides (from methyl ketones) yield homogeneous 1-alkynes only if the 3-position is blocked. (E)-Haloalkenes lead also to alkynes in a syn-elimination process.
- Dehmlow, Eckehard V.,Lissel, Manfred
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