29619-42-9Relevant academic research and scientific papers
Sonogashira coupling and cyclization reactions on alumina: A route to aryl alkynes, 2-substituted-benzo[b]furans and 2-substituted-indoles
Kabalka, George W.,Wang, Lei,Pagni, Richard M.
, p. 8017 - 8028 (2001)
A solventless, microwave-enhanced Sonogashira coupling reaction of aromatic iodides with terminal alkynes on potassium fluoride doped alumina in the presence of palladium powder, cuprous iodide, and triphenylphosphine has been developed. The reaction can be utilized to prepare aryl alkynes in excellent yields. The coupling of o-iodophenol with terminal alkynes leads to the formation 2-substituted-benzo[b]furans. Whereas the coupling of o-iodoanilines with terminal alkynes generates indole products. An in situ desilylation reaction was also developed.
Synthesis and electronic properties of iso-alkyl substituted hexa-peri-hexabenzocoronenes (HBC's) from a versatile new HBC synthon, hexakis(4-acetylphenyl)benzene
Chebny, Vincent J.,Gwengo, Chengeto,Gardinier, James R.,Rathore, Rajendra
, p. 4869 - 4872 (2008)
Simple syntheses of a variety of soluble hexa-peri-hexabenzocoronenes are accomplished using an easily prepared hexakis(4-acetylphenyl)benzene as a common precursor. The concentration-dependent emissions of various HBC's in solution indicate that they undergo extensive aggregation despite the presence of bulky (peripheral) isoalkyl and tert-butyl groups. The various planar HBC's undergo reversible electrochemical oxidations and form stable monomeric cation-radical salts in solution.
"canopy Catalysts" for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework
Copéret, Christophe,Fürstner, Alois,Gordon, Christopher P.,Hillenbrand, Julius,Leutzsch, Markus,N?thling, Nils,Wille, Christian,Yiannakas, Ektoras
supporting information, p. 11279 - 11294 (2020/07/13)
A new family of structurally well-defined molybdenum alkylidyne catalysts for alkyne metathesis, which is distinguished by a tripodal trisilanolate ligand architecture, is presented. Complexes of type 1 combine the virtues of previous generations of silanolate-based catalysts with a significantly improved functional group tolerance. They are easy to prepare on scale; the modularity of the ligand synthesis allows the steric and electronic properties to be fine-tuned and hence the application profile of the catalysts to be optimized. This opportunity is manifested in the development of catalyst 1f, which is as reactive as the best ancestors but exhibits an unrivaled scope. The new catalysts work well in the presence of unprotected alcohols and various other protic groups. The chelate effect entails even a certain stability toward water, which marks a big leap forward in metal alkylidyne chemistry in general. At the same time, they tolerate many donor sites, including basic nitrogen and numerous heterocycles. This aspect is substantiated by applications to polyfunctional (natural) products. A combined spectroscopic, crystallographic, and computational study provides insights into structure and electronic character of complexes of type 1. Particularly informative are a density functional theory (DFT)-based chemical shift tensor analysis of the alkylidyne carbon atom and 95Mo NMR spectroscopy; this analytical tool had been rarely used in organometallic chemistry before but turns out to be a sensitive probe that deserves more attention. The data show that the podand ligands render a Mo-alkylidyne a priori more electrophilic than analogous monodentate triarylsilanols; proper ligand tuning, however, allows the Lewis acidity as well as the steric demand about the central atom to be adjusted to the point that excellent performance of the catalyst is ensured.
Robust Alkyne Metathesis Catalyzed by Air Stable d2Re(V) Alkylidyne Complexes
Cui, Mingxu,Bai, Wei,Sung, Herman H. Y.,Williams, Ian D.,Jia, Guochen
supporting information, p. 13339 - 13344 (2020/09/03)
We report in this communication the first example of catalytic alkyne metathesis reactions mediated by well-defined non-d0 alkylidyne complexes. The air-stable d2 Re(V) alkylidyne complex Re4, bearing two PO-chelating ligands and a labile pyridine ligand, could catalyze homometathesis of internal alkynes with a broad substrate scope, including alcohols, amines, and even carboxylic acids. The catalyst can tolerate heating, air, and moisture in both solid and solution states, and the catalytic metathesis reactions could proceed normally in wet solvents.
One-Pot Domino Synthesis of Diarylalkynes/1,4-Diaryl-1,3-diynes by [9,9-Dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)–Copper(I) Iodide–Palladium(II) Acetate-Catalyzed Double Sonogashira-Type Reaction
Qiu, Shaozhong,Zhang, Caiyang,Qiu, Rui,Yin, Guodong,Huang, Jinkun
, p. 313 - 321 (2018/01/15)
The low loading combination of the complex [9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)copper(I) iodide and simple ligand-free palladium(II) acetate was found to be efficient for the domino synthesis of diarylalkynes by the reaction of aryl halides with trimethylsilylethynylene or bis(trimethylsilyl)acetylene in a single-step procedure. The unsymmetrical diarylalkynes can be obtained through a one-pot two-step approach. The reactions of aryl bromides with 1,4-bis(trimethylsilyl)butadiyne also furnished the corresponding 1,4-diaryl-1,3-diynes in a similar fashion. This route to diarylalkynes and 1,4-diaryl-1,3-diynes is complementary to previously reported synthetic procedures. (Figure presented.).
Preparation and Reactions of Mono- and Bis-Pivaloyloxyzinc Acetylides
Tüllmann, Carl Phillip,Chen, Yi-Hung,Schuster, Robin J.,Knochel, Paul
supporting information, p. 4601 - 4605 (2018/08/09)
Mono-pivaloyloxyzinc acetylide and bis-pivaloyloxyzinc acetylide were selectively prepared from ethynylmagnesium bromide in quantitative yields. These zinc reagents readily underwent Negishi cross-couplings with (hetero)aryl iodides or bromides as well as subsequent Sonogashira cross-couplings. 1,3-Dipolar cycloadditions of these zinc acetylides with benzylic azides produced zincated and bis-zincated triazoles which were trapped with several electrophiles. An opposite regioselectivity compared to the Cu-catalyzed click-reactions was observed.
Synthesis of α,α-Dichloroketones through Sequential Reaction of Decarboxylative Coupling and Chlorination
Cho, Eunjeong,Kim, Myungjin,Jayaraman, Aravindan,Kim, Jimin,Lee, Sunwoo
supporting information, p. 781 - 784 (2018/02/21)
2,2-Dichloro-1,2-diarylethanones were synthesized from diarylalkynes and trichloroisocyanuric acid. The reaction was conducted in CH3CN/H2O at room temperature for 12 h. In addition, the desired 2,2-dichloro-1,2-diarylethanones could be prepared from aryl bromides and propiolic acid through sequential Pd-catalyzed decarboxylative coupling and chlorination. This method showed moderate to good yields and good tolerance toward functional groups such as chlorides, bromides, aldehydes, and ketones.
Preparation method of diaryl acetylene compounds
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Page/Page column 0076; 0077; 0078; 0092; 0113, (2018/05/16)
The invention relates to preparation of an organic compound, and aims to provide a preparation method of diaryl acetylene compounds. The preparation method includes steps of adding associated tribromomethylarene compound and copper in a reactor to perform deoxidizing treatment; dissolving polyamine in a proper amount of anhydrous and oxygen-free solvent, and then adding to the reactor; performingcoupling reaction at 30-80DEG C for 3-12 hours; separating and purifying to obtain diaryl acetylene compounds. The preparation is gentle in synthesis condition and the reaction has good compatibilityto different functional groups; the raw material associated tribromomethylarene compound is convenient to compound and has different substituent groups and variable structure; by adopting one raw material, high-quality product can be obtained through simple treatment, and the output is high; by adopting two different raw materials, the asymmetrical diaryl acetylene compound can be prepared.
High Oxidation State Molybdenum N-Heterocyclic Carbene Alkylidyne Complexes: Synthesis, Mechanistic Studies, and Reactivity
Koy, Maximilian,Elser, Iris,Meisner, Jan,Frey, Wolfgang,Wurst, Klaus,K?stner, Johannes,Buchmeiser, Michael R.
supporting information, p. 15484 - 15490 (2017/11/09)
The first synthetic protocol to high oxidation state molybdenum(VI) N-heterocyclic carbene (NHC) alkylidyne complexes (NHC=1,3-diisopropylimidazol-2-ylidene, 1,3-dimethyl-4,5-R2-imidazol-2-ylidene, R2=H, Cl, CN) is reported. Steric limitations of the NHCs and the benzylidyne are described. All novel complexes were characterized by single crystal X-ray diffraction and solution NMR techniques. It was shown that all complexes presented here show activity in the self-metathesis of 1-phenyl-1-propyne at room temperature. To identify mechanistic differences, an experimental sequence to detect dissociation of ligands was developed. Results reveal dissociation of less electron-donating NHCs in course of the reaction. Mechanistic and reactivity differences were attributed to electronic and steric effects through Tolman's electronic parameter and the percentage of buried volume. Furthermore, Mo-1 containing the 1,3-dimethylimidazol-2-ylidene ligand showed good activity in self-metathesis reactions of p-substituted 1-phenyl-1-propynes with electron-donating moieties at room temperature.
Palladium(II)-Catalyzed Annulation of Alkynes with 2-(Cyanomethyl)phenylboronates Leading to 3,4-Disubstituted 2-Naphthalenamines
Tsukamoto, Hirokazu,Ikeda, Taishi,Doi, Takayuki
, p. 1733 - 1745 (2016/03/15)
1,2-Bis(diphenylphosphino)ethane (dppe)-ligated palladium(II) complexes catalyze the annulation of internal alkynes with 2-(cyanomethyl)phenylboronates to provide 3,4-disubstituted-2-naphthalenamines in good yields. The annulation reaction proceeds under mild and neutral conditions and requires methanol as an essential solvent. In addition to symmetrical alkynes, unsymmetrical alkynes substituted by aryl, alkyl, and alkynyl groups participate in the annulation to afford the corresponding 2-naphthalenamines with electron-withdrawing sp2- and sp-carbons preferentially located at the C-3 position. Substituents including an alkyl or alkoxy group on the cyanomethyl moiety and a halogen atom on the benzene ring in the boronates are compatible with the reaction conditions. The annulation proceeds through the transmetalation of the palladium(II) complexes with the boronates and alkyne insertion followed by nucleophilic addition of the generated alkenylpalladium(II) species to the intramolecular cyano group. Stoichiometric reactions revealed that the methanol solvent was effective for both transmetalation and catalyst regeneration.
