142060-21-7Relevant articles and documents
Probing the Evolution of Palladium Species in Pd@MOF Catalysts during the Heck Coupling Reaction: An Operando X-ray Absorption Spectroscopy Study
Yuan, Ning,Pascanu, Vlad,Huang, Zhehao,Valiente, Alejandro,Heidenreich, Niclas,Leubner, Sebastian,Inge, A. Ken,Gaar, Jakob,Stock, Norbert,Persson, Ingmar,Martín-Matute, Belén,Zou, Xiaodong
supporting information, p. 8206 - 8217 (2018/06/22)
The mechanism of the Heck C-C coupling reaction catalyzed by Pd@MOFs has been investigated using operando X-ray absorption spectroscopy (XAS) and powder X-ray diffraction (PXRD) combined with transmission electron microscopy (TEM) analysis and nuclear magnetic resonance (1H NMR) kinetic studies. A custom-made reaction cell was used, allowing operando PXRD and XAS data collection using high-energy synchrotron radiation. By analyzing the XAS data in combination with ex situ studies, the evolution of the palladium species is followed from the as-synthesized to its deactivated form. An adaptive reaction mechanism is proposed. Mononuclear Pd(II) complexes are found to be the dominant active species at the beginning of the reaction, which then gradually transform into Pd nanoclusters with 13-20 Pd atoms on average in later catalytic turnovers. Consumption of available reagent and substrate leads to coordination of Cl- ions to their surfaces, which causes the poisoning of the active sites. By understanding the deactivation process, it was possible to tune the reaction conditions and prolong the lifetime of the catalyst.
Palladium(II) Acetate Catalyzed Reductive Heck Reaction of Enones; A Practical Approach
Mannathan, Subramaniyan,Raoufmoghaddam, Saeed,Reek, Joost N. H.,De Vries, Johannes G.,Minnaard, Adriaan J.
, p. 3923 - 3927 (2016/01/26)
A surprisingly practical Pd(OAc)2 or Pd(TFA)2-catalyzed reductive Heck reaction between aryl iodides and α,β-unsaturated ketones is described using N,N-diisopropylethylamine (DIPEA, Hünigs base) as the reductant. In general, 1 mol % of Pd(OAc)2 is sufficient to afford good yields using electron-rich or halogen-substituted aryl iodides. Electron-deficient aryl iodides preferentially give homocoupling. Enones containing aryl or bulky substituents on the β-carbon react smoothly, producing mainly reductive Heck product, whereas enones with alkyl substituents on the β-carbon afford a mixture of reductive Heck and Heck product. Deuterium labeling experiments show that the reaction is a bona fide reductive Heck reaction and exclude a Heck reaction-conjugate reduction cascade. Deeply DIPEA about... A palladium-catalyzed reductive Heck reaction of aryl iodides to α,β-unsaturated ketones is described using N,N diisopropylethylamine (DIPEA, Hünigs base) as the reductant. A deuterium labeling study shows that the reaction is a bona fide reductive Heck reaction and excludes a Heck reaction-conjugate reduction cascade.
Simple preparation of 4-aryl- and 4-alkyl-2(5H)-furanones from β-substituted crotonic esters
Kagabu,Shimizu,Ito,Moriya
, p. 830 - 832 (2007/10/02)
Treatment of β-aryl- or β-alkylcrotonic esters with selenium dioxide in acetic acid in the presence of a catalytic amount of perchloric acid gave 4-substituted 2(5H)-furanones in moderate to good yields.
