Cu(ii)-thiophene-2, 5-bis(amino-alcohol) mediated asymmetric Aldol reaction and Domino Knoevenagel Michael cyclization: a new highly efficient Lewis acid catalyst. Issue 10 (21st February 2022)

• Record Type: Journal Article
• Authors: Al-Majid, Abdullah Mohammed; Alammari, Abdullah Saleh; Alshahrani, Saeed; Haukka, Matti; Islam, Mohammad Shahidul; Barakat, Assem
• Is Part Of: RSC advances. Volume 12:Issue 10(2022)
• Page Start: 6149
• Page End: 6165
• Publication Date: 2022-02-21
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2ra00674j
• Languages: English
• ISSNs: 2046-2069

Abstract

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. 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 (2 S, 2′ S )-2, 2′-((thiophene-2, 5-diylbis(methylene))bis(azanediyl))bis(3-phenylpropan-1-ol) (L1 ) in combination with Cu(OAc)2 ·H2 O 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[4 H -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.