Efficient syntheses of angularly fused triquinanes via β-amino-substituted α,β-unsaturated fischer-carbene complexes

Jelena Milic, Heiko Schirmer, Bernard L. Flynn, Mathias Noltemeyer, Armin De Meijere

Research output: Contribution to journalArticleResearchpeer-review

7 Citations (Scopus)


Formal [3+2] cycloadditions of the carbene ligand in the new (3-dimethylamino-1-alkoxyalkenylidene)pentacarbonylchromium complexes 5 and 14 both with cyclopropyl substituents in the 3-position, onto alkynes give 5-dimethylamino-3-ethoxycyclopentadienes 6 and 15a-f, the latter along with regioisomers 16a-d, in good yields (55-72%). Treatment of these with hydrochloric acid liberates two carbonyl groups in each of them, and the resulting 5-dimethylaminocyclopent-1-en-3-ones 7 and 17a-c/18a-c, under basic conditions, undergo a cascade of two cyclizations, to yield angularly fused triquinanes 10 (68%) and 23a-c (30-97%). The overall procedure consists of four operational steps and produces cyclopropane-annelated tricyclo[,5]undecane skeletons from two different alkynes each in 22-47% overall yield.

Original languageEnglish
Pages (from-to)875-878
Number of pages4
Issue number6
Publication statusPublished - 22 Jun 2002
Externally publishedYes


  • Carbenechromium complexes
  • Cascade reactions
  • Cycloadditions
  • Cyclopentadienones
  • Spiro[4.4]nonenones
  • Triquinanes

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