- Copper-Catalyzed Regioselective and Stereoselective Coupling of Grignard Reagents with Pent-1-en-4-yn-3-yl Benzoates: A Shortcut to (Z) -1,5-Disubstituted Pent-3-en-1-ynes from Accessible Starting Materials
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Copper-catalyzed coupling of Grignard reagents with pent-1-en-4-yn-3-yl benzoates occurs regioselectively at the terminal alkenyl carbon rather than the alkynyl site, leading to the stereoselective formation of unexpected (Z)-1,5-disubstituted pent-3-en-1-ynes without generation of the initially expected alkenyl allene products. By using easily accessible starting materials, this reaction can provide direct access to thermodynamically unfavorable Z-configured enynes, which widely exist in many bioactive natural products, such as the anti-inflammatory components in henna.
- Chen, Fenglin,Chen, Yanjiao,Cao, Hongen,Xu, Qing,Yu, Lei
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p. 14158 - 14164
(2018/11/30)
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- Regioselective hydrations of 1-aryl-3-en-1-ynes using gold and platinum catalysts: Selective production of 2-en-1-ones and 3-en-1-ones
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Regiocontrolled hydrations of 1-aryl-3-en-1-ynes have been accomplished with IPrAuOTf and PtCl2/CO to yield 3-en-1-ones and 2-en-1-ones efficiently; our experimental data indicates that the sizes of catalysts play an important role. This journa
- Mokar, Bhanudas Dattatray,Liu, Rai-Shung
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p. 8966 - 8969
(2014/08/05)
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- Cu-catalyzed Fe-driven Csp-Csp and C sp-Csp2 cross-coupling: An access to 1,3-diynes and 1,3-enynes
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An efficient Csp-Csp cross-coupling of alkynyl bromide and pinacol ester of alkynyl boronic acid catalyzed by CuFe 2O4 nanoparticles has been accomplished in dimethyl carbonate to produce unsymmetric 1,3-diynes. This protocol is also extended for the Csp-Csp2 coupling of alkynyl bromide and alkenyl boronic acid to provide conjugated 1,3-enynes. The aliphatic, aromatic, and heteroaromatic alkynes couple with various substituted alkynyl/alkenyl boronates/boronic acids by this procedure to furnish a library of 1,3-diynes and enynes in high yields. The catalyst was easily separated by an external magnet and recycled 10 times.
- Ahammed, Sabir,Kundu, Debasish,Ranu, Brindaban C.
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p. 7391 - 7398
(2014/09/17)
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- Enyne chlorides: Substrates for copper-catalyzed asymmetric allylic alkylation
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A select few: Several prochiral enyne chlorides were employed as substrates in the title reaction using Grignard reagents as the alkylation reagents (see scheme; CuTC=copper(I) thiophenecarboxylate). Excellent 1,3 substitution regioselectivities and good to excellent enantioselectivities were obtained. The substrate scope is additionally extended to diene chlorides. Copyright
- Li, Hailing,Alexakis, Alexandre
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supporting information; experimental part
p. 1055 - 1058
(2012/04/05)
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- Skeletal change in the PNP pincer ligand leads to a highly regioselective alkyne dimerization catalyst
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A Rh complex of a bulky diarylamino-based PNP pincer ligand is a robust catalyst for the dimerization of terminal alkynes and highly selective for the trans-enyne product. The Royal Society of Chemistry 2006.
- Weng, Wei,Guo, Chengyun,Celenligil-Cetin, Remle,Foxman, Bruce M.,Ozerov, Oleg V.
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p. 197 - 199
(2008/02/07)
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- Rearrangement of allylic and propargylic alcohols catalyzed by the combined use of tetrabutylammonium perrhenate(VII) and p-toluenesulfonic acid
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Allylic rearrangement and/or dehydration reaction of allylic alcohols proceeds smoothly by the use of catalytic amounts of tetrabutylammonium perrhenate and p-toluenesulfonic acid hydrate. Treatment of propargylic alcohols with the catalysts at room temperature affords the rearranged products, α,β-unsaturated carbonyl compounds, while β,γ-unsaturated ketones are obtained as main products by the reaction in refluxing 1,2-dichloroethane. The application of this catalytic system is also described for the preparation of some synthetic intermediates.
- Narasaka,Kusama,Hayashi
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p. 2059 - 2068
(2007/10/02)
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- Rearrangement of Allylic and Propargylic Alcohols Catalyzed by the Combined Use of Tetrabutylammonium Perrhenate(VII) and p-Toluenesulfonic Acid
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Allylic rearrangement and/or dehydration of allylic alcohols proceed by the use of a catalytic amount of tetrabutylammonium perrhenate and p-toluenesulfonic acid.Treatment of propargylic alcohols with the above reagents affords the rearranged products, α,β-unsaturated carbonyl compounds.
- Narasaka, Koichi,Kusama, Hiroyuki,Hayashi, Yujiro
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p. 1413 - 1416
(2007/10/02)
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- PHASE-TRANSFER VERSION OF THE WITTIG REACTION AND ITS STEREOCHEMISTRY IN THE ALIPHATIC SERIES
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Alkyltriphenylphosphonium salts react with saturated α,β-ethylenic, α,β-acetylenic, and cyclic aliphatic aldehydes when heated with solid potassium carbonate to form the corresponding alkenes with preparative yields.The reaction is cis-stereoselective with saturated aldehydes and cis-stereospecific with unsaturated aldehydes.
- Khusid, A. Kh.,Kovalev, B. G.
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