- Fast "Wittig-Like" Reactions As a Consequence of the Inorganic Enamine Effect
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(Chemical Equation Presented). The tungsten alkylidyne [CF3-ONO]W≡CC(CH3)3(THF)2 (3) {where CF3-ONO = (MeC6H3[C(CF3)2O])2N3-} supported by a trianionic pincer-type ligand demonstrates enhanced nucleophilicity in unusually fast "Wittig-like" reactions. Experiments are designed to provide support for an inorganic enamine effect that is the origin of the enhanced nucleophilicity. Treating complex 3 with various carbonyl-containing substrates provides tungsten-oxo-vinyl complexes upon oxygen atom transfer. The rates of reactivity of 3 are compared with the known alkylidyne (DIPP)3W≡CC(CH3)3 (DIPP = 2,6-diisopropylphenoxide). In all cases (except acetone), complex 3 exhibits significantly faster overall rates than (DIPP)3W≡CC(CH3)3. New oxo-vinyl complexes are characterized by NMR, combustion analysis and single crystal X-ray diffraction. Treating 3 with acid chlorides provides the tungsten oxo chloride species [CF3-ONO]W(O)Cl (4) and disubstituted alkynes. In the case of acetone the oxo-vinyl complex results in two rotational isomers 10syn and 10anti. The rate of isomerization was determined for the forward and reverse directions and was complimented with DFT calculations.
- Gonsales, Stella A.,Pascualini, Matias E.,Ghiviriga, Ion,Abboud, Khalil A.,Veige, Adam S.
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- Nickel-Catalyzed Sonogashira Coupling Reactions of Nonactivated Alkyl Chlorides under Mild Conditions
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The two nickel chlorides1and2with [P,S] and [P,Se] bidentate ligands, respectively, were synthesized and used as catalysts for Sonogashira coupling reaction. Both1and2are efficient catalysts for Sonogashira C(sp3)-C(sp) coupling reactions. Comp
- Fan, Qingqing,Sun, Hongjian,Xie, Shangqing,Dong, Yanhong,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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p. 2240 - 2245
(2021/04/06)
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- CsF-Mediated in Situ Desilylation of TMS-Alkynes for Sonogashira Reaction
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A practical and mild set of conditions for the Sonogashira reaction utilizing CsF-mediated in situ TMS-alkyne desilylation followed by Sonogashira coupling has been developed for the synthesis of a variety of alkynyl benzenes and heteroarenes in good to excellent yields. This methodology demonstrates excellent functional group tolerance and simple purification, which allows large-scale industrial applications. This one-pot protocol enables a high-yielding Sonogashira coupling with volatile alkynes by avoiding challenging isolation of free alkynes.
- Capani, Joseph S.,Cochran, John E.,Liang, Jianglin
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p. 9378 - 9384
(2019/07/08)
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- A palladium catalyzed aryl alkyne preparation method
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The invention discloses a palladium catalyzed aryl alkyne of the preparation method, comprises the following steps: in the catalyst, under the action of the ligand and alkali, substituted with aryl sulfonyl chloride alkynoic occurs in the organic solvent escapes suosuo the coupling reaction, after the reaction is finished after treatment to obtain the aryl alkyne. Used in the preparation method of the cheap raw material, the reaction and simple post treatment operation, at the same time, the reaction less side reaction, high yield of the product.
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Paragraph 0034; 0035; 0036
(2019/05/21)
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- Pd-Catalyzed decarboxylative alkynylation of alkynyl carboxylic acids with arylsulfonyl hydrazides via a desulfinative process
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In the presence of a Pd(ii)/P-ligand catalytic system, decarboxylative alkynylation of alkynyl carboxylic acids and arylsulfonyl hydrazides by desulfinative coupling could provide aryl alkynes in satisfactory yields by either judiciously selecting palladium catalysts or modulating phosphine ligands under mild conditions. The reported coupling reactions are very practical as they do not require the protection of inert gas or oxygen and are tolerant to many functional groups.
- Chang, Sheng,Liu, Ying,Yin, Shu Zhu,Dong, Lin Lin,Wang, Jian Feng
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supporting information
p. 5357 - 5362
(2019/04/04)
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- Visible light promoted coupling of alkynyl bromides and Hantzsch esters for the synthesis of internal alkynes
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A metal-free visible light promoted C(sp3)-C(sp) coupling reaction of alkynyl bromides and Hantzsch esters was developed, giving internal alkynes with primary, secondary, tertiary alkyl or other functional groups in good to high yields.
- Song, Zhi-Yong,Zhang, Chun-Lin,Ye, Song
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p. 181 - 185
(2019/01/04)
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- Diastereodivergent Reductive Cross Coupling of Alkynes through Tandem Catalysis: Z- and E-Selective Hydroarylation of Terminal Alkynes
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A diastereodivergent hydroarylation of terminal alkynes is accomplished using tandem catalysis. The hydroarylation allows highly selective synthesis of both E and Z diastereoisomers of aryl alkenes, from the same set of starting materials, using the same combination of palladium and copper catalysts. The selectivity is controlled by simple changes in the stoichiometry of the alcohol additive. The hydroarylation has excellent substrate scope and can be accomplished in the presence of various classes of compounds, including esters, nitriles, alkyl halides, epoxides, carbamates, acetals, ethers, silyl ethers, and thioethers. The Z-selective hydroarylation is accomplished using a new approach based on tandem Sonogashira coupling and catalytic semireduction. The E-selective hydroarylation involves an additional catalytic isomerization of the Z-alkene. Our explorations of the reaction mechanism explain the role of individual reaction components and how the subtle changes in the reaction conditions influence the rates of specific steps of the hydroarylation. Our studies also show that, although the Z- and E-selective hydroarylation reactions are mechanistically closely related, the roles of the palladium and copper catalysts in the two reactions are different.
- Armstrong, Megan K.,Goodstein, Madison B.,Lalic, Gojko
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supporting information
p. 10233 - 10241
(2018/08/23)
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- A simple catalyst system for the palladium-catalyzed coupling of aryl halides with terminal alkynes
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A convenient catalyst system consisting of Pd(OAc)2, PPh 3, K3PO4 and DMSO was found to be effective for the coupling reaction of aryl halides with terminal alkynes as well as the deacetonative coupling reaction using a 4-aryl-2-methylbut-3-yn-2-ol as a terminal alkyne precursor. An iminophosphine as a ligand worked more effectively for some combination of substrates than triphenylphosphine.
- Shirakawa, Eiji,Kitabata, Takaaki,Otsuka, Hidehito,Tsuchimoto, Teruhisa
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p. 9878 - 9885
(2007/10/03)
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- Copper-catalyzed cross- and carbonylative coupling reactions of alkynyliodonium salts with organoboronic acids and organostannanes
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Copper-catalyzed cross- and carbonylative coupling reactions have been achieved in the reaction of a variety of alkynyliodonium salts with arylboronic acids and organostannanes under the mild reaction conditions in high yield. Our investigation shows that the alkynylidonium tetrafluoroborates are more efficient than those of triflates and tosylates. Georg Thieme Verlag Stuttgart.
- Yu, Chan-Mo,Kweon, Jae-Hong,Ho, Pil-Su,Kang, Sin-Cheol,Lee, Gong Yeal
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p. 2631 - 2634
(2007/10/03)
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- Carbamoyl-Substituted N-Heterocyclic Carbene Complexes of Palladium(II): Application to Sonogashira Cross-Coupling Reactions
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(matrix presented) The first examples of N-carbamoyl-substituted heterocyclic carbene Pd(II) complexes are described. These thermal and hydrolytically stable complexes are readily prepared from carbamoyl imidazolium salts and efficiently promote Sonogashi
- Batey, Robert A.,Shen, Ming,Lough, Alan J.
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p. 1411 - 1414
(2007/10/03)
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