Publications (20)97.58 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: Novel porous thin-sheet carbon membrane/sintered metal steel fibers (SMFs) composites were developed by the dipping and carbonization process. These novel carbon membrane materials have been characterized by a series of techniques including thermal gravimetric analyses (TGA), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption–desorption method. Adsorption breakthrough curves of isopropanol in the structured fixed bed filled with both activated carbons in the inlet of bed and carbon membrane/SMFs composites in the outlet of bed were investigated, comparing with that in fixed bed containing only activated carbons with the same bed height. The experimental results indicated that the carbon membranes with different thickness from 748.1 nm to 1.27 μm were successfully fabricated on the surface of SMFs support. The length of unused bed (LUB) theory was also employed to study the breakthrough curves. The porous carbon membrane/SMFs composites filled in fixed be show exhibited excellent bed utilization, demonstrating by a lowest LUB value (1.17 cm). The porous carbon membrane/SMFs composites as high efficiency adsorbents can offer a much higher mass transfer efficiency, contacting efficiency as well as adsorption rate.
- [Show abstract] [Hide abstract] ABSTRACT: The copper-catalyzed cycloamination reaction of 1,1-dibromoalkenes with amidines affords a diverse set of polysubstituted haloimidazole derivatives. By using this strategy, high regio- and chemoselectivity has been achieved, using 4,7-diphenyl-1,10-phenanthroline as ligand without the addition of expensive catalysts to provide moderate to good yields. The copper-catalyzed cycloamination reaction of 1,1-dibromoalkenes with amidines affords a diverse set of polysubstituted haloimidazole derivatives. Moderate to good yields with high regio- and chemoselectivities were achieved by using 4,7-diphenyl-1,10-phenanthroline as ligand without the addition of expensive catalyst.
- [Show abstract] [Hide abstract] ABSTRACT: An efficient copper-promoted hydration reaction and its application in the synthesis of benzo[b]furan and benzo[b]thiophene derivatives is presented starting from readily available 2-fluorophenylacetylene derivatives. The key annulation step involves the hydration of the C-F bond of 2-fluorophenylacetylene derivatives followed by an intramolecular annulation to afford benzo[b]furan and benzo[b]thiophene derivatives. Moreover, structurally important 2,2'-bisbenzofuran scaffolds are provided in good yields.
- [Show abstract] [Hide abstract] ABSTRACT: Different generation hyperbranched polyurethanes (HBPUs) were synthesized through the A2+B'B2 strategy. The molecular structures and viscosity were characterized by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The NMR results confirmed the formation of the branched units between the segments contained in the HBPU structure. The GPC with a four-capillary bridge design differential viscometer and the Ubbelohde viscometer showed a different viscosity. For the HBPUs, the viscosity first increased to higher values then decreased to lower values, and finally increased with increasing weight, which can be attributed to the spherical structure. The growth degree of HBPUs spherical structure depends on the forming hydrogen bonds; when the hydrogen bonds reach a certain degree, the spherical structure becomes compact.
- [Show abstract] [Hide abstract] ABSTRACT: A novel palladium-catalyzed cyclization of bromoacrylamides with isocyanides gives substituted 2,5-diimino-furans, which can be used as the precursor of maleamides. This reaction presumably proceeds through the oxygen atom of the amide moiety of the bromoacrylamides coordinated to the Pd(ii) centre as a key step.
- [Show abstract] [Hide abstract] ABSTRACT: Unsaturated bicyclic carboxylic acids undergo palladium-catalyzed coupling with bromoalkynes to produce γ-alkynyl lactones in moderate to good yields with excellent chemo- and regioselectivity. The reaction conditions were extremely mild, and functional groups such as methyl, methoxy, chloro, and bromo were tolerated under the optimized reaction conditions. Moreover, γ-chloroalkenyl lactones were facilely synthesized through chloropalladation/carboesterification of electron-deficient C≡C bonds by using molecular oxygen as the sole oxidant.
- [Show abstract] [Hide abstract] ABSTRACT: The difunctionalization of terminal alkynes was achieved with silver fluoride (AgF) and N-bromosuccinimide (NBS) as halogen sources. The presence of the halide moiety greatly enhances the reactivity of the vinyl fluoride compounds that can probably can be transformed into various products that are difficult or even impossible to obtain via direct fluorination. Meanwhile, the monofluoro <.> alkenes were facilely synthesized via a highly chemo- and regioselective fluorination of electron-deficient C C triple bonds using AgF as fluorinating reagent in good yields.
- [Show abstract] [Hide abstract] ABSTRACT: A palladium-catalyzed, one-pot cyclization reaction to construct (3E)-(imino)isoindolin-1-ones and (3E)-(imino)thiaisoindoline 1,1-dioxides by introducing ortho-reactive functional groups on aryl halides is reported. Under optimal conditions, the cyclization reaction afforded the corresponding products in good to excellent yields (up to 93%) with high stereoselectivity. Notably, this transformation successfully extends its application for the synthesis of phenanthridines and dibenzooxazepines. This new synthetic protocol not only extends the application platform for palladium-catalyzed C-C coupling of aryl halides with isocyanides,but also opens atom-economic and step-economic synthetic routes for nitrogen-containing heterocyclic compounds with wide functional group compatibility.
- [Show abstract] [Hide abstract] ABSTRACT: A series of substituted quinolines was prepared from arylamines, aldehydes, and terminal olefins (see scheme). The palladium-catalyzed sequential formation of C-C bonds proceeds smoothly with both electron-deficient and electron-rich olefins. When acrylic acid is used as terminal olefin, decarboxylation occurs to provide 2-substituted quinolines.
- [Show abstract] [Hide abstract] ABSTRACT: A robust route to 4-amine-benzo[b][1,4]oxazepines relying upon a palladium-catalyzed tandem reaction of o-aminophenols, bromoalkynes and isocyanides has been developed. This chemistry presumably proceeds through the migratory insertion of isocyanides into the vinyl-palladium intermediate as a key step.
- [Show abstract] [Hide abstract] ABSTRACT: A regioselective synthesis of 2,5-disubstituted furans using copper(I) catalyst from haloalkynes in a one-pot procedure has been reported. This chemistry proceeds through the hydration reaction of 1,3-diynes, which can be readily prepared from the coupling reaction of haloalkynes in the presence of CuI. The procedure also can be used for the facile synthesis of 2,5-disubstituted thiophenes.
- [Show abstract] [Hide abstract] ABSTRACT: The palladium-catalyzed and CsF-promoted annulation reaction of bromoalkynes and isocyanides regioselectively affords a diverse set of 5-iminopyrrolone derivatives. This chemistry presumably proceeds through the bromoacrylamide intermediates, which can be readily prepared from the nucleophilic addition reaction of isocyanides to bromoalkynes in the presence of CsF.
- [Show abstract] [Hide abstract] ABSTRACT: The reactions proceed under extremely mild conditions and tolerate various functional groups.
- [Show abstract] [Hide abstract] ABSTRACT: The palladium-assisted one-pot three-component reactions of aldehydes, amines and olefins proceeded smoothly to give 2,6-unsubstituted 1,4-dihydropyridines (1,4-DHPs) using molecular oxygen as a sole oxidant. It also provides efficient Pd-catalyzed aerobic oxidation access to the anti-Markovnikov oxidative amination products of olefins from primary aromatic amines and alkenes. The method is atom-efficient, using cheap and easily available starting materials and an environmentally benign oxidant.
- [Show abstract] [Hide abstract] ABSTRACT: A new and efficient method for the synthesis of amides via palladium-catalyzed C-C coupling of aryl halides with isocyanides is reported, by which a series of amides were formed from readily available starting materials under mild conditions. This transformation could extend its use to the synthesis of natural products and significant pharmaceuticals.
- [Show abstract] [Hide abstract] ABSTRACT: The easily accessible haloalkynes can be converted to (Z)-2-halo-1-iodoalkenes in high yields with excellent regio- and stereoselectivity. The method shows good functional group compatibility. The resulting products could find broad applications.
- [Show abstract] [Hide abstract] ABSTRACT: Direct cis-addition of bromoalkynes (I) to symmetrical alkyne (II) proceeds in the presence of a Pd(II) catalyst to give difunctionalized enyne products (III) in high yields.
- [Show abstract] [Hide abstract] ABSTRACT: A new silver-catalyzed highly regio- and stereoselective difunctionalization reaction of simple terminal alkynes was reported in which the (Z)-beta-haloenol acetate derivatives were formed efficiently. The resulting products were versatile intermediates in organic synthesis.
- [Show abstract] [Hide abstract] ABSTRACT: (Chemical Equation Presented) Side by side: Direct cis addition of bro-moalkynes 1 to various alkynes 2 was found to proceed in the presence of a PdII catalyst to give difunctionalized enyne products 3. The method is facile for the synthesis of bromo alkenynes. Further-more, an unusual mechanism is pro-posed.
Wuyi UniversityChiang-men-shih, Guangdong, China
South China University of Technology
Shengcheng, Guangdong, China
- Department of Chemical Engineering