Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Filtros adicionais











Intervalo de ano
1.
Org Lett ; 21(8): 2786-2789, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-30939026

RESUMO

An annulation cascades of N-allyl- N-((2-bromoaryl)ethynyl)amides with terminal alkynes or 1,3-dicarbonyls involving C-H functionalization for producing 2,3-functionalized indoles has been first developed by means of Cu catalysis. The method is enabled by the formation of the ketenimine intermediates to deliver 2,3-disubstituted indoles through a sequence of aza-Claisen rearrangement, C-H functionalization, Ullmann C-N coupling, and cyclization.

2.
J Org Chem ; 83(15): 8581-8588, 2018 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-29871487

RESUMO

A new metal-free oxidative decarbonylative [3+2] annulation of terminal alkynes with tertiary alkyl aldehydes is presented, which features broad substrate scope and excellent selectivity. The selectivity of this reaction toward cyclopentenes and indenes relies on the nature of the aldehyde substrates. While treatment of tertiary γ,δ-unsaturated aldehydes with common terminal alkynes assembles cyclopentenes, 2-methyl-2-arylpropanals succeed in accessing indenes.

3.
Nat Commun ; 8: 14720, 2017 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-28393864

RESUMO

Difunctionalization of alkenes has become a powerful tool for quickly increasing molecular complexity in synthesis. Despite significant progress in the area of alkene difunctionalization involving the incorporation of a nitrogen atom across the C-C double bonds, approaches for the direct 1,2-carboamination of alkenes to produce linear N-containing molecules are scarce and remain a formidable challenge. Here we describe a radical-mediated oxidative intermolecular 1,2-alkylamination of alkenes with alkyl nitriles and amines involving C(sp3)-H oxidative functionalization catalysed by a combination of Ag2CO3 with iron Lewis acids. This three-component alkene 1,2-alkylamination method is initiated by the C(sp3)-H oxidative radical functionalization, which enables one-step formation of two new chemical bonds, a C-C bond and a C-N bond, to selectively produce γ-amino alkyl nitriles.

4.
Org Lett ; 18(9): 2012-5, 2016 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-27123866

RESUMO

A practical and straightforward access to pyrazolo[3,4-c]quinolines by molecular sieve mediated dehydrogenative [2 + 2 + 1] heteroannulation of N-(o-alkenylaryl)imines with aryldiazonium salts is described using a sp(3)-hybrid carbon atom as a one-carbon unit. The reaction enables the formation of three new chemical bonds, a C-C bond and two C-N bonds, in a single reaction and features simple operation and excellent functional group tolerance.

5.
Chem Commun (Camb) ; 51(10): 1886-8, 2015 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-25529927

RESUMO

We describe here a new metal-free route for the synthesis of 3-nitroindoles by the nitrative cyclization of N-aryl imines with tert-butyl nitrite. The radical transformation allows the assembly of the indole framework through oxidative cleavage of multi C-H bonds, a nitration, cyclization and isomerization cascade.


Assuntos
Iminas/química , Indóis/química , Nitritos/química , Ciclização , Indóis/síntese química , Metais , Estrutura Molecular , Nitrocompostos/química
6.
Chem Commun (Camb) ; 50(85): 12867-9, 2014 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-25212419

RESUMO

A new oxidative coupling of unactivated terminal alkenes with amides using peroxides is described, in which mono- and difunctionalization of alkenes are selectively achieved. In this reaction with amides, the chemoselectivity toward the functionalization of the C(sp(3))-H bonds adjacent to the nitrogen atom or the functionalization of the carbonyl C(sp(2))-H bonds across alkenes relies on the reaction conditions.

7.
Chem Commun (Camb) ; 50(52): 6906-8, 2014 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-24840629

RESUMO

A novel route to Δ(2)-isoxazolines is presented via silver-mediated radical cyclization of α-halo ketoximes with 1,3-dicarbonyl compounds. This method is performed using a radical strategy, and represents a new example of silver-initiated generation of oxime radicals for the formation of the C(sp(3))-O bonds.


Assuntos
Derivados de Benzeno/química , Radicais Livres/química , Hidrocarbonetos Halogenados/química , Isoxazóis/síntese química , Oximas/química , Prata/química , Ciclização , Modelos Moleculares , Estrutura Molecular
8.
J Org Chem ; 79(3): 1025-31, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24417252

RESUMO

A new route is presented for the selective assembly of isoquinolines and indenes by rhodium-catalyzed tandem cyclization of benzylidenehydrazones with internal alkynes. This method involves the selective cleavage of the N-N bond and the C═N bonds and is dependent on the substituents of the benzylidenehydrazone.


Assuntos
Alquinos/química , Hidrazinas/química , Indenos/síntese química , Isoquinolinas/síntese química , Ródio/química , Catálise , Indenos/química , Isoquinolinas/química , Estrutura Molecular
9.
J Org Chem ; 78(20): 10421-6, 2013 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-24053535

RESUMO

A novel palladium-catalyzed methylation protocol for the synthesis of methyl-functionalized internal alkynes has been established. This methylation method is achieved through a C(sp)-C(sp(3)) bond formation process and represents a new synthetic application of sulfonium ylides.


Assuntos
Alquinos/química , Paládio/química , Compostos de Sulfônio/química , Compostos de Sulfônio/síntese química , Ligações de Hidrogênio , Metilação , Estrutura Molecular
11.
J Org Chem ; 75(10): 3484-7, 2010 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-20373751

RESUMO

A selective protocol for the synthesis of 2-methylene-3-substituted-2,3-dihydro-1H-inden-1-ones and 2-benzylidene-2,3-dihydro-1H-inden-1-ones has been developed via palladium-catalyzed cyclocarbonylation reactions of arynes with allyl carbonates and carbon monooxide (CO). It is noteworthy that the selectivity of this new route is depended on both substrates and ligands.


Assuntos
Alquinos/química , Compostos Alílicos/química , Carbonatos/química , Indenos/síntese química , Paládio/química , Monóxido de Carbono/química , Catálise , Ciclização , Indenos/química , Estrutura Molecular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA