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1.
Org Lett ; 22(5): 2070-2075, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32096641

RESUMO

We present herein a rare and efficient method for the creation of vinylated all carbon quaternary centers via Fe-catalyzed cross-electrophile coupling of vinyl halides with tertiary alkyl methyl oxalates. The reaction displays excellent functional group tolerance and broad substrate scope, which allows cascade radical cyclization and vinylation to afford complex bicyclic and spiral structural motifs. The reaction proceeds via tertiary alkyl radicals, and the putative vinyl-Br/Fe complexation appears to be crucial for activating the alkene and enabling a possibly concerted radical addition/C-Fe forming process.

2.
Org Biomol Chem ; 14(48): 11332-11335, 2016 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-27878154

RESUMO

This work describes the vinylation of α-halo carbonyl compounds with vinyl bromides under Ni-catalyzed reductive coupling conditions. While aryl-conjugated vinyl bromides entail pyridine as the sole labile ligand, the alkyl-substituted vinyl bromides require both bipyridine and pyridine as the co-ligands.

3.
Langmuir ; 27(19): 11958-65, 2011 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-21905651

RESUMO

A novel organic-inorganic hybrid 2D molecular space with regular triphenylphosphine groups (triphenylphosphineamidephenylsilica, PPh(3)APhS) was successfully synthesized through grafting triphenylphosphine groups in the 2D structure of layered aminophenylsilica dodecyl sulfate (APhTMS-DS), which was developed in our previous research, with regular ammonium groups. The 2D structures were kept after the grafting reaction of triphenylphosphine groups in PPh(3)APhS. The catalytic potentials of 2D molecular space with regular triphenylphosphine groups were investigated. An unusual catalytic effect was found in a carbon-phosphorus ylide reaction. The PPh(3)-catalyzed reaction of modified allylic compounds, including bromides and chlorides with tropone yielded a [3 + 6] annulation product. However, an unusual [8 + 3] cycloadduct was obtained in the reaction of modified allylic compounds, including bromides and chlorides with tropone catalyzed by PPh(3)APhS. Otherwise, the stable catalytic intermediate was successfully separated, and the reaction activity of the catalytic intermediate was confirmed in the reaction of modified allylic compounds with tropone catalyzed by PPh(3)APhS. This research is the first successful example of directly influencing catalytic reaction processes and product structures by utilizing the chemical and geometrical limits of 2D molecular spaces with regular catalyst molecules and affords a novel method for controlling catalytic reaction processes and catalyst design.


Assuntos
Compostos Organofosforados/química , Compostos de Organossilício/química , Dióxido de Silício/química , Catálise , Estrutura Molecular , Compostos de Organossilício/síntese química
4.
Langmuir ; 25(10): 5993-9, 2009 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-19296641

RESUMO

Novel two-dimensional molecular space with regular pyridine groups layered pyridine-4-amidepropylsilica (PAPS) and pyridine-4-amidephenylsilica (PAPhS) were successfully synthesized through grafting pyridine groups in the layer structure of two-dimensional molecular space with regular ammonium groups layered aminopropylsilica (ATMS-DS) and layered aminophenylsilica (APhTMS-DS). The two-dimensional structures were kept after grafting reaction of pyridine groups in PAPS and PAPhS. The catalytic potentials of two-dimensional molecular space with regular ammonium and pyridine groups were investigated. The catalytic capability of APhTMS-DS, PAPS, and PAPhS was confirmed through Knoevenagel condensation reactions. Knoevenagel condensation of aromatic aldehydes with malononitrile was not observed in the presence of ATMS-DS. Otherwise, the lower yield of Knoevenagel condensation of higher active 2-chlorobenzaldehyde with malononitrile in the presence of APhTMS-DS, PAPS, and PAPhS indicated the potential of the two-dimensional molecular space with regular catalyst molecules on influencing catalysis processes utilizing the chemical and geometrical limits.

5.
Langmuir ; 24(1): 302-9, 2008 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18041857

RESUMO

A novel two-dimensional molecular space (layered carboxylpropylamidephenylsilica, CPAPhS) with regular carboxyl groups was successfully synthesized through grafting carboxyl groups in the structure of layered (aminophenyl)silica using butanedioic anhydride. The carboxyl groups regularly arranged in the layered CPAPhS can react with various organic molecules with amino and hydroxyl groups through formation of reactive intermediate with catalyzers, such as SOCl2. In this research, an example was used to prove the reaction properties of regular carboxyl groups in layered CPAPhS. The layered CPAPhS was reacted with SOCl2 to form layered acyl chloridepropylamidephenylsilica (ACPAPhS) and then reacted with n-butylamine and n-butyl alcohol to form layered n-butylamidepropylamidephenylsilica (BAPAPhS) and n-butylesterpropylamidephenylsilica (BEPAPhS) with regular molecular structures. Layered CPAPhS showed the potential as a starting material for formation of a series of novel two-dimensional molecular space with various regular molecular structures, and as a solid acceptor for chemical reagent with amino and hydroxyl groups for chemical processes.

6.
J Colloid Interface Sci ; 315(1): 400-4, 2007 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-17689551

RESUMO

A novel reactive layered two-dimensional molecular space material [layered chloroacetamide phenyl silica (CAAPhS)] with regular chlorine groups was synthesized by grafting chlorine groups into the layer structure of layered aminophenyl silica. The reactive activity of chlorine groups regularly arranged in the layer structure of layered CAAPhS was confirmed through a substitution reaction with n-butylamine. Layered CAAPhS showed potential as a starting material for the formation of a series of two-dimensional layered materials with various regular functional molecules and organic-inorganic composite materials.

7.
J Colloid Interface Sci ; 285(1): 259-66, 2005 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-15797421

RESUMO

A novel strategy for the synthesis of layered organosilica is demonstrated. The ionic interaction between the anionic group of a surfactant (sodium dodecyl sulfate) and the cationic organic group of an organosilane (3-aminopropyltrimethoxysilane, ATMS) under acidic conditions was utilized to create a layered organosilica at room temperature. The inorganic part of the organosilica layer was an Si-O hexagonal sheet, and organofunctional groups were alternately arranged on both sides of the sheet. The layered structure of the ATMS organosilica was retained after the removal of the surfactant with chloride anion. The properties of the layered ATMS organosilica were investigated. The layered ATMS-Cl organosilica is stable and possesses a definite layer structure in water or ethanol. Various kinds of anions can be intercalated in the interlayer space of the layered ATMS organosilicas and the layer was expanded dependent on the intercalated anions. The structure of the layered ATMS organosilica was well retained during the intercalation processes.

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