Using triethynylphosphine ligands bearing bulky end caps to create a holey catalytic environment: application to gold(I)-catalyzed alkyne cyclizations

J Am Chem Soc. 2006 Dec 27;128(51):16486-7. doi: 10.1021/ja066800c.

Abstract

The synthesis, properties and catalytic uses of phosphinoalkynes bearing bulky end caps at the alkyne termini, that is, tris[(triarylsilyl)ethynyl]phosphines are reported. The most salient feature of the new phosphines is the holey molecular shape possessing a deep and large-scale metal-binding cavity. The holey phosphines displayed remarkable rate enhancement in the gold(I)-catalyzed six- and seven-membered ring forming cyclizations of acetylenic keto esters and 1,7-enynes. It is proposed that the cavity in the ligand forces a nucleophilic center (enol or alkene) of the acetylenic compounds close to the gold-bound alkyne, making ring-closing anti attack feasible.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylene / analogs & derivatives*
  • Acetylene / chemistry
  • Alkynes / chemical synthesis*
  • Alkynes / chemistry
  • Catalysis
  • Cyclization
  • Gold / chemistry*
  • Ligands
  • Molecular Structure
  • Phosphines / chemistry*
  • Porosity
  • Stereoisomerism

Substances

  • Alkynes
  • Ligands
  • Phosphines
  • triethynylphosphine
  • Gold
  • Acetylene