Issue 10, 2022

Cu(ii)-thiophene-2,5-bis(amino-alcohol) mediated asymmetric Aldol reaction and Domino Knoevenagel Michael cyclization: a new highly efficient Lewis acid catalyst

Abstract

The highly efficient Lewis acid-catalytic system Cu(II)-thiophene-2,5-bis(amino-alcohol) has been developed for enantioselective Aldol reaction of isatin derivatives with ketones. The new catalytic system also proved to be highly enantioselective for the one pot three-component Domino Knoevenagel Michael cyclization reaction of substituted isatin with malononitrile and ethylacetoacetate. The chiral ligand (2S,2′S)-2,2′-((thiophene-2,5-diylbis(methylene))bis(azanediyl))bis(3-phenylpropan-1-ol) (L1) in combination with Cu(OAc)2·H2O employed as a new Lewis acid catalyst, furnished 3-substituted-3-hydroxyindolin-2-ones derivatives (3a–s) in good to excellent yields (81–99%) with high enantioselectivities (up to 96% ee) and spiro[4H-pyran-3,3-oxindole] derivatives (6a–l) in excellent yields (89–99%) with high ee (up to 95%). These aldol products and spiro-oxindoles constitute a core structural motif in a large number of pharmaceutically active molecules and natural products.

Graphical abstract: Cu(ii)-thiophene-2,5-bis(amino-alcohol) mediated asymmetric Aldol reaction and Domino Knoevenagel Michael cyclization: a new highly efficient Lewis acid catalyst

Supplementary files

Article information

Article type
Paper
Submitted
31 Jan 2022
Accepted
09 Feb 2022
First published
21 Feb 2022
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2022,12, 6149-6165

Cu(II)-thiophene-2,5-bis(amino-alcohol) mediated asymmetric Aldol reaction and Domino Knoevenagel Michael cyclization: a new highly efficient Lewis acid catalyst

A. M. Al-Majid, A. S. Alammari, S. Alshahrani, M. Haukka, M. S. Islam and A. Barakat, RSC Adv., 2022, 12, 6149 DOI: 10.1039/D2RA00674J

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