could be soaked with palladium(0) from palladium salts, the formate counteranion being the reducing source. The resulting Amberlite resin formate supported with palladium(0), ARF-Pd, showed excellent catalytic activity in Heck, Suzuki-Miyaura, and Sonogashira couplings with a range of substrates. The catalyst may be recovered easily and quantitatively without leaching and recycled; it was tested for
The present invention relates to a method of producing a heterogeneous catalyst suitable for catalyzing Heck, Suzuki-Miyaura Sonogashira coupling and Buchwald-Hartwig reactions, comprising the steps of: a) providing a macroporous carrier, said macroporous carrier consisting of a core and a plurality of ion exchange groups covalently bonded to the surface of said core, where at least 90% of the ions bound to said carrier are formate ions; b) swelling said carrier in a polar solvent; c) providing a palladium (II) salt; d) suspending said carrier in an organic solvent thereby obtaining a suspension; e) adding said palladium salt to said suspension and allowing the resulting mixture to react at a temperature within the range of 0 70° C. until said carrier has turned black; f) washing said carrier in water; g) drying said carrier under vacuum.
Gold‐Catalyzed 1,2‐Dicarbofunctionalization of Alkynes with Organohalides**
作者:Shashank P. Sancheti、Yukta Singh、Manoj V. Mane、Nitin T. Patil
DOI:10.1002/anie.202310493
日期:2023.10.16
The first report of 1,2-dicarbofunctionalization of alkynes using organohalides as coupling partners in the field of goldcatalysis has been presented. Mechanistic investigations, including NMR, tandem mass spectrometry and DFT studies, reveal that an oxidative addition/carbophilic activation pathway is preferred over the migratory insertion/cis-trans isomerization pathway.
Cationic and macroporous amberlite resins with formate (HCOO−) as the counter anion (ARF) have been used to prepare a new class of heterogeneous Pd/Cu bimetallic composite nanoparticles (NPs) (Pd/Cu–ARF). The physicochemical characteristics of Pd/Cu–ARF were examined with the help of FTIR spectroscopy, X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and atomic absorption spectroscopy (AAS). XRD and TEM showed the existence of composite NPs made of metallic Pd, PdO and CuO. The TEM analysis revealed fairly uniform distributions of composite NPs of average size ∼4.9 nm. The as-synthesized nanocomposite material (Pd/Cu–ARF) exhibited high catalytic activity in the Sonogashira cross-coupling reaction between aryl iodide and terminal alkynes. Heterogeneity of the catalytic activity was evidenced from different tests (hot-filtration and catalyst-poisoning experiments) and the recycling ability of the catalyst was examined for five consecutive runs without any significant loss of activity.