Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chem Sci ; 13(35): 10448-10454, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36277643

RESUMO

A serendipitous and highly efficient approach for the construction of a variety of δ-carboline derivatives was developed through base-promoted cascade ß-F-elimination/electrocyclization/Diels-Alder/retro-Diels-Alder reaction of N-2,2,2-trifluoroethylisatin ketoimine esters with alkynes in good to high yields with excellent regio-/chemoselectivity control. Moreover, a reasonable reaction pathway was proposed, which was in accordance with the prepared reaction intermediate and control experiment results. The δ-carboline product could be easily converted into a new chiral Py-box-type ligand through simple synthetic transformations. This salient strategy featured the advantages of metal-free conditions, excellent regio-/chemoselectivity, good to high yields, and outstanding substrate tolerance. Importantly, the potential application of these fascinating δ-carboline derivative products is well demonstrated in the recognition of ferric ions.

2.
Chem Commun (Camb) ; 57(64): 7958-7961, 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34286725

RESUMO

Herein we reported a highly diastereoselective synthesis of quaternary 3-amino oxindoles bearing an acetal unit via a palladium catalyzed three-component cascade umpolung allylation/acetalation process. An array of 3-amino 3-allyl oxindoles incorporating diversified functional groups were prepared in good yields with exclusive diastereoselectivities. Further investigation demonstrated that the current method could also be extended to cascade umpolung allenylation/acetalation.

3.
Chem Commun (Camb) ; 56(22): 3333-3336, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32090227

RESUMO

Facile access to quaternary α-trifluoromethyl α-amino acids has been developed. This sequential reaction involves an Ir-catalyzed asymmetric allylation of α-trifluoromethyl aldimine esters followed by an unprecedented kinetic resolution.


Assuntos
Aminoácidos/química , Irídio/química , Aminoácidos/síntese química , Catálise , Cristalografia por Raios X , Iminas/química , Cinética , Conformação Molecular , Estereoisomerismo
4.
Chem Sci ; 11(40): 10984-10990, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34094346

RESUMO

In this study, we developed an efficient Ir-catalyzed cascade umpolung allylation/2-aza-Cope rearrangement of tertiary α-trifluoromethyl α-amino acid derivatives for the preparation of a variety of quaternary α-trifluoromethyl α-amino acids in high yields with excellent enantioselectivities. The umpolung reactivity empowered by the activation of the key isatin-ketoimine moiety obviates the intractable enantioselectivity control in Pd-catalyzed asymmetric linear α-allylation. In combination with quasi parallel kinetic resolution or kinetic resolution, the generality of this method is further demonstrated by the first preparation of enantioenriched quaternary trifluoromethyl ß-, γ-, δ- and ε-amino acid derivatives.

5.
Org Lett ; 21(12): 4842-4848, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31145631

RESUMO

An unprecedented Ir-catalyzed asymmetric cascade umpolung allylation/2-aza-Cope rearrangement of trifluoroethylisatin ketimines has been realized. The current method provides a facile access to biologically important α-trifluoromethyl-containing homoallylic amines in high yields with excellent enantioselectivity. Notably, umpolung reactivity of trifluoroethylisatin ketimine was discovered for the first time. Mechanism studies revealed the key intermediates in the initial umpolung allylation and the stereospecific chirality transfer in the subsequent 2-aza-Cope rearrangement.

6.
Org Lett ; 21(4): 1191-1196, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30707591

RESUMO

The first example of highly efficient kinetic resolution of exo-3-oxodicyclopentadienes and endo-3-oxodicyclopentadiene has been developed by means of Cu(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide. Compared with the existing methodologies for those synthetically important optically active convex molecules, the current protocol provides an alternative but more practical approach from the readily available racemic starting materials, which is free from the repetitive reduction/oxidation steps in the enzymatic resolution or the indispensable stoichiometric amount of chirality-induction reagents.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...