Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes

Ken Ichiro Imamura, Eiji Yoshikawa, Vladimir Gevorgyan, Tomoko Sudo, Naoki Asao, Yoshinori Yamamoto

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18 Scopus citations


The EtAlCl2-mediated intramolecular addition of silyl enol ethers to both terminal and internal unactivated alkynes, bearing alkyl and phenyl susbstituents at the alkyne moiety, gave mono- and bicyclic β,γ-unsaturated ketones in good to excellent yields. On the other hand, the silyloxy-substituted cyclic vinylsilanes were obtained in moderate to high yields when the reactions were catalyzed by B(C6F5)3 in the presence of triethylsilane. All the reactions proceeded via endo-fashion exclusively. The mechanisms of these regiospecific Lewis acid-assisted carbocyclizations are proposed.

Original languageEnglish (US)
Pages (from-to)1624-1631
Number of pages8
JournalCanadian Journal of Chemistry
Issue number11
Publication statusPublished - Jan 1 2001
Externally publishedYes



  • Alkynes
  • Carbocyclization
  • Lewis acid
  • Silyl enol ethers

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

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