ENANTIOSELECTIVE [2+2+2] CYCLOISOMERISATION OF ALKYNES IN THE SYNTHESIS OF HELICENES: THE SEARCH FOR EFFECTIVE CHIRAL LIGANDS

Irena G. Stara, Angelina Andronova, Adrian Kollarovic, Stepan Vyskocil, Sylvain Juge, Guy C. Lloyd-Jones, Patrick J. Guiry, Ivo Stary

Research output: Contribution to journalArticlepeer-review

Abstract

The enantioselective [2+2+2] cycloisomerisation of the aromatic triynes under nickel(0) catalysis to afford nonracemic [6]- and [7]helicene derivatives has been systematically studied. A collection of mono-and bidentate phosphines, phosphites, phosphinites and phosphinous amides possessing stereogenic units such as chiral centre, axis or plane (or their combinations) has been tested and axially chiral binaphthyl-derived monodentate MOP-type phosphine ligands were the optimal class of ligands. Nickel complexes of these ligands afforded nonracemic tetrahydro [6]helicene in up to 64% ee in a model reaction.

Original languageEnglish
Pages (from-to)2005-2022
Number of pages18
JournalCollection of czechoslovak chemical communications
Volume76
Issue number12
DOIs
Publication statusPublished - 2011

Keywords

  • Helicenes
  • Alkynes
  • Cycloisomerisation
  • Nickel catalysis
  • Phosphorus ligands
  • Enantioselectivity
  • Chirality
  • Asymmetric catalysis
  • ASYMMETRIC CATALYSIS
  • QUINAZOLINAP LIGANDS
  • PHOSPHINITE LIGANDS
  • COUPLING REACTIONS
  • AROMATIC TRIYNES
  • RESOLUTION
  • MOLECULES
  • ROUTE
  • HYDROGENATION
  • HYDROBORATION

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