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1.
Fully substituted triazoles were synthesized via the four-component coupling reaction of unactivated silylacetylenes, two equivalents of allyl carbonates, and trimethylsilyl azide in the presence of a Pd(0)-Cu(I) bimetallic catalyst. Various trisubstituted 1,2,3-triazoles were obtained in good yields. The reaction most probably proceeds through the [3+2] cycloaddition reaction between the alkynylcopper species and azide followed by the cross-coupling reaction between the vinylcopper intermediate and π-allylpalladium complex. 相似文献
2.
Karandeep Singh Bhanwar Kumar Malviya Ved Prakash Verma Satpal Singh Badsara Vimal K. Bhardwaj Siddharth Sharma 《Tetrahedron》2019,75(17):2506-2520
A divergent regioselective palladium (II) catalyzed approach through post Ugi cyclization is described. The Ugi adduct underwent intramolecular ortho-hydroarylation via 6-endo-dig cyclization for the direct access to 4-aryl-2-quinolones. Incorporation of iodine at the C-3 position of 2-quinolone followed by Suzuki-Miyaura coupling results into the more diversified 3,4-diaryl-2-quinolones. 相似文献
3.
The activity of dimeric [Pd{C6H2(CH2CH2NH2)-(OMe)2-3,4}(μ-Br)]2 and monomeric [Pd{C6H2(CH2CH2NH2)-(OMe)2-3,4}Br(PPh3)] complexes as efficient, air, and moisture tolerant catalysts was investigated in Stille and Hiyama cross-coupling reactions of various aryl halides. Substituted biaryls were produced in excellent yields in short reaction times using these complexes. The monomeric complex had been demonstrated to be more active than the corresponding dimeric catalyst for the cross-coupling of some of aryl bromides and unreactive aryl chlorides. The combination of homogenous metal catalyst, microwave irradiation, and microwave-active polar solvents gave high yields of products in short reaction times. 相似文献
4.
Lidiya G. Fedenok Mark S. Shvartsberg Valentina S. Bashurova George A. Bogdanchikov 《Tetrahedron letters》2010,51(1):67-8924
The cyclization of ortho-(arylethynyl)benzene diazonium salts (the Richter reaction) is studied. A reaction mechanism, which differs radically from that reported earlier is proposed and substantiated by experimental data and quantum-chemical calculations. 相似文献
5.
Lidiya G. FedenokNataliya A. Zolnikova 《Tetrahedron letters》2003,44(29):5453-5455
Cyclization of ortho-(phenylethynyl)benzene diazonium salts containing groups of +C character at the para-position of the phenyl ring proceeds with closure to a pyrazole, but not to a pyridazine as is the case in the presence of neutral or −C groups. 相似文献
6.
Sung Hwan Kim 《Tetrahedron letters》2010,51(5):860-3242
Various 3,3-diallyl isoindolones were synthesized via a indium-mediated Barbier type double allylation reaction of ortho-cyanobenzoates in good yields in short time. The reactivity of nitrile group toward allylindium is sufficient to form a cyclic compound when a suitable electrophilic center is present in the same molecule to trap the imine intermediate. 相似文献
7.
Gregory D. Cuny 《Tetrahedron letters》2004,45(26):5167-5170
A synthesis of the alkaloid (±)-aporphine is reported. The initial key step of the synthesis involves a Pictet-Spengler cyclization of N-tosyl tyramine with 2-bromophenylacetaldehyde in trifluoroacetic acid. This step was followed by the second strategic transformation a palladium-mediated intramolecular phenol ortho-arylation reaction utilizing tricyclohexylphosphine as co-catalysts in the presence of cesium carbonate. Finally, de-oxygenation of the phenol, removal of the tosyl group and methylation gave the desired alkaloid. 相似文献
8.
Ponnaboina Thirupathi 《Tetrahedron》2010,66(45):8623-8628
Indium triflate-catalyzed allylation reactions of N-sulfonyl aldimines or N-alkoxyloxycarbonylamino p-tolylsulfone with allyltrimethylsilane have been successfully developed to produce protected homoallylic amines. 相似文献
9.
The zwitterionic intermediates (2a) in the oxidation of ortho-alkylphenols (1) and bis(sulfonium ylide) 3 form reasonably stable 2:1-complexes (4), in which the ortho-quinone methide (oQM) moieties are not present in quinoid form with the exocyclic in-plane methylene group, but as zwitterionic, aromatic conformer having an out-of-plane exocyclic methylene group. The complex 7 derived from the α-tocopherol model compound PMC (5) was comprehensively characterized. As exemplarily demonstrated, the adducts can be advantageously employed in organic synthesis as ‘stabilized oQMs’. 相似文献
10.
Biswanath Das Kongara Damodar Darshanala Saritha Nikhil Chowdhury Martha Krishnaiah 《Tetrahedron letters》2007,48(45):7930-7933
The Sakurai reaction of N-alkoxycarbonylamino sulfones with allyltrimethylsilane in the presence of a catalytic amount of indium(III) chloride at room temperature produces the corresponding protected homoallylic amines in high yields. 相似文献
11.
A cationic palladium complex catalyzed arylative cyclization reaction of N-(2-formylaryl)alkynamides with arylboronic acids was developed. This new process provides an efficient way for the synthesis of functionalized 2-quinolinones in good to excellent yields under mild conditions. Some control experiments were conducted to explain the possible mechanism for the formation of the products. 相似文献
12.
Glycosylation of the acid labile protopanaxadiol derivatives was succeeded with a glycosyl ortho-hexynylbenzoate as donor under the catalysis of PPh3AuNTf2, leading to the subsequent elaboration of ginsenoside Rh2 and chikusetsusaponin-LT8 in a concise manner. 相似文献
13.
Jin Zhou 《Journal of organometallic chemistry》2009,694(5):697-12741
A series of water-soluble diimine ligands were applied for the Suzuki reaction of arylbromide in different media. Low loading of catalyst (0.01 mol%) were necessary for the coupling reaction to proceed in water or water/ethanol. The catalytic system was found to tolerate a broad range of functional groups. 相似文献
14.
Nazhen Liu 《Journal of organometallic chemistry》2011,696(13):2537-370
Dibenzylphenylphosphine in the reaction with CoMe(PMe3)4 afforded complex [(Me3P)3Co((ortho-C6H4)∩P(C6H5)(CH2C6H5))] (1) by Csp2-H activation via ortho-metalation with P atom as anchoring group. An unexpected dinitrogen iron(II) complex [(Me3P)2(N2)Fe((ortho-C6H4)2∩P(C6H5))] (2) stabilized by two five-membered chelate rings as [CPC]-pincer ligand was formed through the reaction of dibenzylphenylphosphine with FeMe2(PMe3)4 via double Csp2-H activation. The reactions of complexes 1 and 2 with carbon monoxide delivered carbonyl complexes [(Me3P)(CO)2Co((ortho-C6H4)∩P(C6H5)(CH2C6H5))] (3) and [(Me3P)2(CO)Fe((ortho-C6H4)2∩P(C6H5))] (4). An iodo methyl cobalt(III) complex [(Me3P)2(Me)(I)Co((ortho-C6H4)∩P(C6H5)(CH2C6H5))] (5) was isolated through the reaction of 1 with iodomethane. The structures of 1, 2, 3, 4 and 5 were determined by X-ray diffraction. 相似文献
15.
Olga V. Vinogradova 《Tetrahedron letters》2009,50(46):6358-6941
Cleavage of ortho-(dodeca-1,3-diynyl)triazenes in HCl or HBr medium and subsequent cyclization of the resulting diazonium salts is investigated. In the absence of a strong electron-withdrawing substituent, the reaction affords 3-alkynyl-4-bromo(chloro)cinnolines as the only product. A methoxycarbonyl group promotes hydrolysis of 4-halocinnolines which results in the formation of by-products: furo[3,2-c]cinnoline and cinnolinone. Substitution of bromine in 3-(alk-1-ynyl)-4-bromocinnolines is achieved with methylamine, Na2S and ethynylbenzene affording pyrrolo[3,2-c]cinnoline, thieno[3,2-c]cinnoline and 3,4-diethynylcinnoline, respectively. 相似文献
16.
2-(4-Chlorophenyl)-2-methyl-1,3-dioxolane 2a was lithiated ortho to the ketal group by treatment with butyllithium in THF at 0°C. Related 2-aryl-2-methyl-1,3-dioxolanes possessing a chlorine substituent at the meta position of the aryl group 2b,c were lithiated with butyllithium in THF at −78°C at the position between the two directing groups. The lithio species thus generated were treated with various electrophiles to give ortho-functionalized acetophenone derivatives. 相似文献
17.
Copper-catalyzed tandem reaction of ortho-bromobenzamides and isothiocyanates is described, which provides an efficient and practical route for the synthesis of 2-thioxo-2,3-dihydroquinazolin-4(1H)-ones. The optimal condition involved the following parameters: CuI as precatalyst, Cs2CO3 as base, N,N′-dimethylethane-1,2-diamine as ligand, and toluene as solvent, with reaction temperature at 120 °C. 相似文献
18.
Novel pyrrolopyridines have been synthesized by an efficient, regioselective and catalytic method from commercially available and inexpensive 3-aminopyridine or 2-aminopyridine. 相似文献
19.
ortho-Alkynylphenyl thioglycosides, prepared readily via Sonagashira coupling of ortho-bromophenyl thioglycosides with alkynes, could undergo glycosidation effectively under the catalysis of a gold(I) complex. 相似文献