Kim S, Lee JH, Yoon SH, Kim I. A regioselective [4 + 2] annulation approach to 5-acylindolizine-7-carbonitriles: generation of poly-substituted pyridines.
Org Biomol Chem 2021;
19:5806-5817. [PMID:
34113946 DOI:
10.1039/d1ob00788b]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of β-ketonitrile and N-substituted pyrrole-2-carboxaldehyde in the presence of piperidinium acetate in CH3CN permitted regioselective access to 5-acylindolizine-7-carbonitrile through a domino Knoevenagel condensation-intramolecular aldol cyclization sequence. A wide range of new indolizine derivatives with a poly-functionalized pyridine moiety were readily synthesized in an atom-economical fashion, thereby expanding the indolizine chemical space for further applications.
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