Exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls proceeding via C-H activation pathway

J Am Chem Soc. 2008 Apr 30;130(17):5636-7. doi: 10.1021/ja8006534. Epub 2008 Mar 22.

Abstract

The first example of the palladium-catalyzed exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls has been demonstrated. In contrast to the reported earlier carbocyclizations proceeding via the Friedel-Crafts mechanism, this hydroarylation efficiently proceeds with electron-neutral and electron-deficient arenes, producing fluorene frameworks with defined stereochemistry of the double bond. On the basis of the high reactivity of electron-deficient arenes toward cyclization, high values of inter- and intramolecular kinetic isotope effects, and the exclusive cis-selectivity of cyclization, a mechanism involving a C-H activation motif has been proposed for this transformation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alkynes / chemistry*
  • Carbon / chemistry
  • Catalysis
  • Cyclization
  • Fluorenes / chemistry
  • Hydrogen / chemistry
  • Models, Chemical
  • Palladium / chemistry*
  • Polycyclic Aromatic Hydrocarbons / chemical synthesis*

Substances

  • Alkynes
  • Fluorenes
  • Polycyclic Aromatic Hydrocarbons
  • fluorene
  • Palladium
  • Carbon
  • Hydrogen