Sequential five-membered ring formation via intramolecular alkene insertion and intramolecular allene insertion to a π-allylpalladium intermediate

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Abstract

Palladium(0)-catalyzed tandem cyclization of 6-allyl-2,7-octadienyl acetate 4 afforded the trans-fused bicyclo[3.3.0]octane 5 by intramolecular alkene insertion to a π-allylpalladium intermediate with 5-exo mode, followed by another intramolecular alkene insertion to the resulting σ-alkylpalladium intermediate. The reaction of 6, a methyl substituted derivative at the 7 position, also provided the novel trans-fused 7 and 8 whereas that of 11 which has dimethyl groups at the 2 and 7 position lead to 12 via 6-exo cyclization. Intramolecular reactions of the π-allylpalladium intermediates to allene moieties afforded two modes of cyclization (15 → 16 and 32 → 33). The former reaction was applied to a synthesis of isoiridomyrmecin (31). A domino cyclization of acyclic 41 was achieved via five and six consecutive carbon-carbon bond formations to successfully provide tricyclic 44 and tetracyclic 43.

Original languageEnglish
Pages (from-to)1190-1194
Number of pages5
JournalYuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry
Volume59
Issue number12
DOIs
Publication statusPublished - 2001 Dec

Keywords

  • 5-membered ring
  • Acetate
  • Allene
  • Allylation
  • Carbonylation
  • Cyclization
  • Domino reaction
  • Insertion
  • Palladium
  • π-ally-palladium

ASJC Scopus subject areas

  • Organic Chemistry

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