Wang L, Mu H, Sun Y, Jin Y, Zhang W. Asymmetric synthesis of spiro[4H-chromene-3,3'-oxindoles] via a squaramide-organocatalytic three-component cascade Knoevenagel/Michael/cyclization sequence.
Mol Divers 2024:10.1007/s11030-024-10852-6. [PMID:
38687399 DOI:
10.1007/s11030-024-10852-6]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 03/18/2024] [Indexed: 05/02/2024]
Abstract
Asymmetric synthesis of spiro[4H-chromene-3,3'-oxindole] derivatives was realized through an organocatalytic cascade Knoevenagel/Michael/cyclization reaction using a quinidine-derived squaramide. Under the optimized conditions, the reactions of isatins, malononitrile, and sesamol yield the desired spirooxindoles in good yields (75-87%) and moderate to high ee values (up to 90% ee).
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