- Synthesis of Non-Terminal Alkenyl Ethers, Alkenyl Sulfides, and N-Vinylazoles from Arylaldehydes or Diarylketones, DMSO and O, S, N-Nucleophiles
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A transition-metal-free protocol for the synthesis of non-terminal alkenyl ethers, alkenyl sulfides, and N-vinylazoles from arylaldehydes or diarylketones, DMSO and O, S, N-nucleophiles has been reported. In this protocol, 24 examples of non-terminal alkenyl ethers and 28 examples of non-terminal alkenyl sulfides in 72–95% yields have been synthesized within 5 min. Moreover, 27 examples of non-terminal N-vinylazoles with 57–88% yields have also been synthesized within 2 hours. The preliminary mechanism investigations revealed that arylaldehydes or diarylketones offered a carbon atom, DMSO provided a methine and O, S, N-nucleophiles contributed one X atom for constructing C=C?X structure. (Figure presented.).
- Nie, Zhiwen,Lv, Huifang,Yang, Tonglin,Su, Miaodong,Luo, Weiping,Liu, Qiang,Guo, Cancheng
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supporting information
p. 1473 - 1480
(2022/04/03)
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- MeOTf/KI-catalyzed efficient synthesis of 2-arylnaphthalenesviacyclodimerization of styrene oxides
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The MeOTf/KI-catalyzed synthesis of 2-arylnaphthalene derivatives from aryl ethylene oxides in alcohol under ambient conditions is described. The present protocol has a higher atom efficiency and wider substrate applicability with excellent yields. The reaction proceeded using the aryl ethylene oxides to give 2-arylnaphthalenes either in homo-coupling or in cross-coupling. The reaction could also be carried out at the gram scale in minutes.
- Chen, Chao,Xi, Chanjuan,Zhang, Zeyu,Zou, Song
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supporting information
p. 8559 - 8565
(2021/10/20)
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- Variation on the π-Acceptor Ligand within a RhI?N-Heterocyclic Carbene Framework: Divergent Catalytic Outcomes for Phenylacetylene-Methanol Transformations
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A series of neutral and cationic rhodium complexes bearing IPr {IPr=1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-carbene} and π-acceptor ligands are reported. Cationic species [Rh(η4-cod)(IPr)(NCCH3)]+ and [Rh(CO)(IPr)(L)2]+ (L=pyridine, CH3CN) were obtained by chlorido abstraction in suitable complexes, whereas the cod-CO derivative [Rh(η4-cod)(IPr)(CO)]+ was formed by the carbonylation of [Rh(η4-cod)(IPr)(NCCH3)]+. Alternatively, neutral derivatives of type RhCl(IPr)(L)2 {L=tBuNC or P(OMe)3} can be accessed from [Rh(μ-Cl)(η2-coe)(IPr)]2. In addition, the mononuclear species Rh(CN)(η4-cod)(IPr) was prepared by cyanide-chlorido anion exchange, which after carbonylation afforded the unusual trinuclear compound [Rh{1κC,2κN-(CN)}(CO)(IPr)]3. Divergent catalytic outcomes in the phenylacetylene-methanol transformations have been observed. Thus, enol ethers, arisen from hydroalkoxylation of the alkyne, were obtained with neutral Rh?CO catalyst precursors whereas dienol ethers were formed with cationic catalysts. Variable amounts of alkyne dimerization, cyclotrimerization or polymerization products were obtained in the absence of a strong π-acceptor ligand on the catalyst.
- Galiana-Cameo, María,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.,Di Giuseppe, Andrea,Castarlenas, Ricardo
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p. 2947 - 2957
(2021/07/16)
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- Base-promoted stereoselective hydroalkoxylation of alkynes
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Base-promoted and stereoselective synthesis of C(sp2)-O bond through the anti-Markovnikov addition of alcohols onto alkyne and has been discovered. Developed protocol tolerates a wide variety of functional groups to afford styryl ethers from commercially
- Patel, Monika,Sushmita,Verma, Akhilesh Kumar
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p. 169 - 175
(2018/09/14)
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- Z-selective, anti-Markovnikov addition of alkoxides to terminal alkynes: An electron transfer pathway?
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Potassium alkoxides undergo anti-Markovnikov addition to aryl-substituted alkynes with Z selectivity in DMF as the solvent. The yields and efficiency of the reaction was also found to be enhanced by the addition of a secondary amine ligand such as N,N′-di
- Cuthbertson, James,Wilden, Jonathan D.
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p. 4385 - 4392
(2015/06/08)
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- Intermolecular Hydroalkoxylation of Terminal Alkynes Catalyzed by a Dipyrrinato Rhodium(I) Complex with Unusual Selectivity
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An operationally simple and atom-economical method for the E-selective preparation of enol ethers is described. A novel dicarbonyl(5-phenyldipyrrinato)rhodium complex, 2, was prepared in four synthetic steps, characterized by X-ray crystallography and NMR
- Lam, Raphael H.,Walker, D. Barney,Tucker, Matthew H.,Gatus, Mark R. D.,Bhadbhade, Mohan,Messerle, Barbara A.
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supporting information
p. 4312 - 4317
(2015/09/22)
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- Rhodium-catalyzed anti-Markovnikov intermolecular hydroalkoxylation of terminal acetylenes
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We report here the first transition-metal-catalyzed anti-Markovnikov intermolecular hydroalkoxylation of terminal acetylenes to give enol ethers in high yields without using bases. Arylacetylenes as well as alkenyl- and alkylacetylenes were coupled with aliphatic alcohols, and the products were obtained with high Z selectivity in most cases. Effective catalysts were 8-quinolinolato rhodium complexes, which are structurally simple but have been relatively unexplored as catalysts.
- Kondo, Masataka,Kochi, Takuya,Kakiuchi, Fumitoshi
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supporting information; experimental part
p. 32 - 34
(2011/03/16)
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- Practical regioselective method for (E)-enol ehter
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A new practical and highly regioselective synthetic method for (E)-enol ether is reported. (E)-enol ethers (E:Z = 93:7-99:1) were prepared from the corresponding enol acetates (E:Z?3:1) in two steps by bromination and anti- elimination of α-bromodialkylac
- Park, Hyeung-Geun,Kim, Dong-Hwa,You, Misuk,Park, Mi-Kyoung,Jew, Sang-Sup
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p. 4579 - 4582
(2007/10/03)
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- Solvolysis of styryliodonium salt: Products, rates, and mechanisms
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The solvolysis of phenyl[(E)-styryl]iodonium tetrafluoroborate in various solvents was examined at 50-70°C by means of product and kinetic studies with the normal and labeled substrates. The reactions involved are α-elimination and substitutions with configurational retention and inversion. In methanol and ethanol, the main reaction is α-elimination, along with about 5% of substitution with the ratio of inversion/retention from 4/6 to 3/7. As the basicity of the solvent decreases, the reaction rate and the fraction of α-elimination decrease, and at the same time the ratio of inversion/retention of substitution also decreases. In 2,2,2- trifluoroethanol, only the substitution with retention was observed. Labeling experiments showed that complete isotope scrambling occurred between the olefinic hydrogens of the retained product while the deuterium remained at the original position of the inverted product. The substitution mechanism is concluded to involve parallel pathways: an S(N) 1-type with a vinylenebenzenium ion intermediate leading to retention and a vinylic S(N) 2- type with a direct attack by the nucleophilic solvent leading to inversion.
- Okuyama, Tadashi,Ishida, Yoshimi,Ochiai, Masahito
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p. 163 - 170
(2007/10/03)
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- Cesium hydroxide catalyzed addition of alcohols and amine derivatives to alkynes and styrene
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In the presence of catalytic amounts of cesium hydroxide (CsOH · H2O), alcohols, substituted anilines and heterocyclic amines undergo an addition in NMP to phenylacetylene leading to functionalized enol ethers and enamines. Anilines add to styrene (90-120°C, 12-14 h) leading to N-substituted anilines in satisfactory yields.
- Tzalis, Dimitrios,Koradin, Christopher,Knochel, Paul
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p. 6193 - 6195
(2007/10/03)
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- New insight into the mechanism of catalytic hydrogenation allows the structure of the key intermediate in asymmetric hydrogenation to be predicted
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An approach has been developed to determine the regioselectivity of hydrometalation in homogeneous and heterogeneous hydrogenation of alkenes. By studying the electronic effects on the orientation of hydrometalation it is found with palladium and rhodium that this key step is a two electron process that can occur by two modes (a Pd(δ*+-) H(δ-) or b Pd(δ-)- H(δ+)). This provides valuable information about the structure of the metal-alkyl intermediate and helps rationalise how chiral induction occurs.
- Yu, Jinquan,Spencer, Jonathan B.
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p. 15821 - 15832
(2007/10/03)
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- LICKOR-Promoted 1,2-elimination in 1,1-dimethoxy-2-phenylethane and 1,1-dimethoxy-2-phenylpropane: synthesis of substituted enol ethers and alkynes
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Dimethyl acetals of phenylacetaldehyde 1a and 2-phenylpropionaldehyde 1b, upon treatment with 1.25 equiv. of LICKOR reagent, undergo 1,2-elimination (THF at -95 deg C) promoted by metallation at the benzylic site, and afford the corresponding enol ethers in the E-form.When the substrate is treated with excess of the base (2.5 equiv.), further hydrogen-metal exchange takes place at the α-vinyl site of the elimination product, and carbonyl electrophiles can be added to the carbanionic intermediate yielding allyl alcohols.Experimental procedures are given for the conversion of the α-substituted derivatives into carbonyl compounds, according to an inverse polarity approach.Moreover, allyl alcohols synthesized starting from 1a, can be transformed into prop-2-ynyl alcohols by treatment with LICKOR base.
- Deagostino, Annamaria,Mella, Mariella,Prandi, Cristina,Venturello, Paolo
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p. 2757 - 2760
(2007/10/02)
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- NUCLEOPHILIC ADDITION TO ALKYNES IN SUPERBASIC CATALYTIC SYSTEMS. IV. VINYLATION OF ALCOHOLS BY PHENYLACETYLENE. A PATH TO PHENYLACETALDEHYDE AND ITS ACETALS
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A method is proposed for the synthesis of phenylacetaldehyde, involving nucleophilic addition of methanol to phenylacetylene in the potassium hydroxide-DMSO system followed by acid-catalyzed hydrolysis of the obtained methyl styryl ether.Electrophilic addition of alcohols and glycerol to the latter in the presence of p-toluenesulfonic acid leads to high yields of the corresponding acetals of phenylacetaldehyde.
- Tarasova, O. A.,Mikhailova, A. I.,Shmidt, E. Yu.,Polovnikova, R. I.,Trofimov, B. A.
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p. 860 - 862
(2007/10/02)
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- COMPETITION BETWEEN VINYLIC SUBSTITUTION AND CONJUGATE ADDITION IN THE REACTIONS OF VINYL SELENOXIDES AND VINYL SELENONES WITH NUCLEOPHILES IN DMF
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Vinyl selenoxides and vinyl selenones present a different reactivity towards thiolate or alkoxide anions in DMF.In the case of selenoxides the addition of the nucleophiles regioselectively occurs at the α-carbon leading to the formation of the vinylic sub
- Tiecco, Marcello,Chianelli, Donatella,Testaferri, Lorenzo,Tingoli, Marco,Bartoli, Donatella
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p. 4889 - 4896
(2007/10/02)
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- FORMATION AND REACTIVITY OF THE ADDITION PRODUCTS OF ALKOXIDES AND THIOLATE ANIONS TO VINYL SELENONES
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Vinyl selenones react with sodium methanethiolate in methanol to give the product of conjugate addition and subsequent displacement of the selenonyl group.On the contrary, the same reaction carried out with alkoxide anions affords the conjugate addition products in excellent yields.These β-alkoxy alkyl phenyl selenones are stable compounds which can react in several ways with loss of the selenonyl group.Their reactions with MeONa or MeSNa have been investigated both in MeOH and in DMF.The products observed derive from substitution and elimination processes as well as from retro Michael reactions followed by nucleophilic substitution of the vinyl selenone thus generated.These results indicate that the ArSeO2 is a strong electron attracting group with peculiar properties.Beside making acidic the α-hydrogen atoms it activates the carbon-carbon double bond towards the addition of anionic reagents and it acts as a good leaving group in nucleophilic substitution, both aliphatic and vinylic, and in elimination reactions.The appropriate choice of the reagent and of the solvent allows to direct the reaction towards the desired products.Useful synthetic applications of these reactions are presented.
- Tiecco, Marcello,Chianelli, Donatella,Tingoli, Marco,Testaferri, Lorenzo,Bartoli, Donatella
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p. 4897 - 4906
(2007/10/02)
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- SYNTHETIC APPLICATION OF PHENYLTHIO- AND PHENYLSULFONYLMETHYL ETHERS TO ALDEHYDES, METHYLALS, CARBOXYLIC ACIDS, AND ENOL OR DIENOL ETHERS
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Novel synthetic application of the title compounds to aldehydes, methylals, carboxylic acids, and enol or dienol ethers has been newly developed.
- Mandai, Tadakatsu,Hara, Kiyomi,Nakajima, Tsukasa,Kawada, Mikio,Otera, Junzo
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p. 4993 - 4996
(2007/10/02)
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- The Allopolarization Principle and its Applications, IV. Substituent Effects in the Methylation of Enolate Anions
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The ratio of O- and C-methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethylketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents.In some cases the influence of solvents, concentration and temperature has also been studied.
- Gompper, Rudolf,Vogt, Hans-Hubert
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p. 2866 - 2883
(2007/10/02)
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- SOLVOLYTIC CLEAVAGE OF ALKENYLPENTAFLUOROSILICATES CATALYZED BY COPPER(II) ACETATE. A STEREOSELECTIVE SYNTHESIS OF (E)-ALKENYL ETHERS FROM ALKYNES
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(E)-Alkenylpentafluorosilicates, obtainable from acetylenes via hydrosilylation-silicate formation, react with alcohols in the presence of a catalytic amount of copper(II) acetate under an atmosphere of air (oxygen) at room temperature to form (E)-alkenyl ethers stereoselectively in satisfactory yields.Similar reaction with water gives aldehydes.
- Tamao, Kohei,Kakui, Toshio,Kumada, Makoto
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p. 4105 - 4108
(2007/10/02)
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