267901-56-4Relevant academic research and scientific papers
Novel Pd(II)- and Pt(II)-catalyzed regio- and stereoselective trans-hydroarylation of alkynes by simple arenes
Jia, Chengguo,Lu, Wenjun,Oyamada, Juzo,Kitamura, Tsugio,Matsuda, Kenji,Irie, Masahiro,Fujiwara, Yuzo
, p. 7252 - 7263 (2000)
Efficient trans-hydroarylation of alkynes by simple arenes has been realized regio- and stereoselectively at room temperature in the presence of Pd(II) or Pt(II) catalysts and a mixed solvent containing trifluoroacetic acid (TFA). Various arenes undergo trans-hydroarylation selectively across terminal and internal C - C triple bonds - including those conjugated to CHO, COMe, CO2H, and CO2Et groups, affording kinetically controlled cis-arylalkenes predominantly in most cases, especially, in good yields for electron-rich arenes and activated alkynes. The formation of arene/alkyne 1/2 or 2/1 adducts as side products is dependent on the arenes' and alkynes' substituents, which can be suppressed in some cases by changing the catalyst, catalyst concentration, and reaction time. The Pt(II) system, PtCl2/2AgOAc/TFA, shows lower catalytic activity than Pd(OAc)2/TFA, but higher selectivity, giving higher yields of adducts at the same conversion. On the basis of several isotope experiments and control reactions, a possible mechanism involving electrophilic metalation of aromatic C - H bonds by in-situ-generated cationic Pd(II) and Pt(II) species leading to intermolecular trans-arylpalladation to alkyes has been discussed.
Reactions of acetylene ketones in superacids
Aristov,Vasil'ev,Fukin,Rudenko
, p. 691 - 705 (2008/02/08)
Vinyl type cations ArC+=CHCOR generated from acetylene ketones ArC+ = CCOR in superacids HSO3F and CF3SO 3H react with diverse benzene derivatives to form alkenylation products, E-/Z-isomers of diaryl
Metal triflate-catalyzed regio- And stereoselective friedelCrafts alkenylation of arenes with alkynes in an ionic liquid: Scope and mechanism
Yoon, Mi Young,Kim, Jin Hong,Choi, Doo Seoung,Shin, Ueon Sang,Lee, Jin Yong,Song, Choong Eui
, p. 1725 - 1737 (2008/02/11)
In the metal triflate-catalyzed hydroarylation of alkynes, employing an ionic liquid dramatically enhanced the catalytic activities, resulting in broadening the scope of substrates (arenes and alkynes). In some cases, even reactions that were not possible in conventional organic solvents proceeded smoothly in ionic liquids. Moreover, the ionic liquid phase containing catalyst could be readily recovered by simple decantation of the organic layer after reaction and reused for the following runs without any significant loss of activity. Mechanistic studies including 13C NMR analysis of reaction intermediates and isotope experiments confirmed for the first time that this type of reaction proceeds via vinyl cationic intermediates.
