C≡C triple bond activation by heterocyclic aluminum phosphinides

Hauke Westenberg, J. Chris Slootweg, Alexander Hepp, Jutta Kösters, Steffi Roters, Andreas W. Ehlers, Koop Lammertsma, Werner Uhl

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Treatment, of aryl-di(tert-butylethynyl)phosphines Aryl-P(C≡C- CMe3)2 [Aryl = C6H5 (4) 2,4,6-Me3C6H2 (5)] with dialkylaluminum hydrides, R2Al-H (R = CMe3, CH2CMe 3), afforded heterocyclic, zwitterionic compounds 6-9 by hydroalumination and release of the corresponding dimeric tert-butylethynyl- dialkylaluminum derivatives, [R2Al-C≡C-CMe3] 2 (10 and 11). The molecular structures of 6-8 reveal a P 2C2Al ring with a tetracoordinated aluminum atom, two exocyclic C=C double bonds, a tricoordinated phosphorus atom, and a phosphonium cation carrying an aryl and an alkynyl group. The C≡C triple bond of 7 was inserted into the Al-P bonds of the heterocycles upon warming to give the bicyclic compound 13. A similar compound (12) was directly formed when the bisalkyne 4 was treated with dineopentylaluminum hydride. Their molecular structures show the annulated four- (AlC2P) and five-membered heterocycles (P2C3) to contain three different C=C double bonds. The sterically most shielded monocyclic compound (8; Aryl = 2,4,5-Me 3C6H2; R = CMe3) decomposed upon warming. DFT calculations were used to examine these reactions.

Original languageEnglish
Pages (from-to)1323-1330
Number of pages8
Issue number6
Publication statusPublished - 22 Mar 2010
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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