Enantioselective Solvent-Free Synthesis of 3-Alkyl-3-hydroxy-2-oxoindoles Catalyzed by Binam-Prolinamides

BINAM-prolinamides are very efficient catalyst for the synthesis of non-protected and N-benzyl isatin derivatives by using an aldol reaction between ketones and isatins under solvent-free conditions. The results in terms of diastereo- and enantioselectivities are good, up to 99% de and 97% ee, and h...

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Bibliographic Details
Published in:Molecules
Main Authors: Bañón Caballero, Abraham, Flores Ferrándiz, Jesús, Guillena, Gabriela, Nájera, Carmen
Other Authors: Universidad de Alicante. Departamento de Química Orgánica, Universidad de Alicante. Instituto Universitario de Síntesis Orgánica, Catálisis Estereoselectiva en Síntesis Orgánica (CESO), Síntesis Asimétrica (SINTAS)
Format: Article in Journal/Newspaper
Language:English
Published: MDPI 2015
Subjects:
Isatin
Aldol
Enantioselectivity
Solvent-free
Prolinamide
Supported catalyst
Química Orgánica
Orca
Online Access:http://hdl.handle.net/10045/48628
https://doi.org/10.3390/molecules200712901
Description
Summary:BINAM-prolinamides are very efficient catalyst for the synthesis of non-protected and N-benzyl isatin derivatives by using an aldol reaction between ketones and isatins under solvent-free conditions. The results in terms of diastereo- and enantioselectivities are good, up to 99% de and 97% ee, and higher to those previously reported in the literature under similar reaction conditions. A high variation of the results is observed depending on the structure of the isatin and the ketone used in the process. While 90% of ee and 97% ee, respectively, is obtained by using (Ra)-BINAM-l-(bis)prolinamide as catalyst in the addition of cyclohexanone and α-methoxyacetone to free isatin, 90% ee is achieved for the reaction between N-benzyl isatin and acetone using N-tosyl BINAM-l-prolinamide as catalyst. This reaction is also carried out using a silica BINAM-l-prolinamide supported catalyst under solvent-free conditions, which can be reused up to five times giving similar results. This work was financially supported by the Ministerio de Economia y Competitividad (MINECO: Projects: CTQ2010-20387 and Consolider INGENIO CSD2007-0006), FEDER, the Generalitat Valenciana (Prometeo/2009/039, the University of Alicante and the EU (ORCA action CM0905). A.B.-C. thanks the Spanish MICINN for a predoctoral fellowship (FPU AP2009-3601).

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