Oh my Gold! Gold atoms stabilise catalytically active palladiumnanoparticles when engaged in an alloy heterogenised on carbon. The increased durability makes the Pd–Au/C catalyst more recyclable than the gold‐free Pd/C catalyst for the Sonogashirareaction.
functions (sulfonic acid moieties) (Pd/CM) was developed. It was used as a catalyst for hydrogenation and ligand-freecross-coupling reactions, such as the Suzuki–Miyaura, Mizoroki–Heck, and copper- and amine-free Sonogashira-type reactions, together with a palladium catalyst supported on monolithic polymer (Pd/AM) bearing basic anion exchange functions (ammonium salt moieties), which has been in practical
Catalytic Efficiency of a New Tridentate Ferrocenyl Phosphine Auxiliary: Sonogashira Cross-Coupling Reactions of Alkynes with Aryl Bromides and Chlorides at Low Catalyst Loadings of 10<sup>-</sup><sup>1</sup> to 10<sup>-</sup><sup>4</sup> Mol %
作者:Jean-Cyrille Hierso、Aziz Fihri、Régine Amardeil、Philippe Meunier、Henri Doucet、Maurice Santelli、Vladimir V. Ivanov
DOI:10.1021/ol048870z
日期:2004.9.1
see text] The catalytic activity in Sonogashira cross-coupling reactions of alkynes with a variety of aryl halides (including chlorides) using a multidentate ferrocenyl phosphine is presented. The novel mixed ferrocenyl aryl/alkyl triphosphine is thermally stable and insensitive to air or moisture, and its robustness allows arylalkynylation at 10(-1) to 10(-4) mol % catalyst loadings with TONs up to
Sonogashira Reaction of Aryl and Heteroaryl Halides with Terminal Alkynes Catalyzed by a Highly Efficient and Recyclable Nanosized MCM-41 Anchored Palladium Bipyridyl Complex
A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further runs without significant loss of reactivity.
Cascading Radical Cyclization of Bis-Vinyl Ethers: Mechanistic Investigation Reveals a 5-<i>exo</i>/3-<i>exo</i>/retro-3-<i>exo</i>/5-<i>exo</i> Pathway
作者:Natasha F. O’Rourke、Katherine A. Davies、Jeremy E. Wulff
DOI:10.1021/jo301565u
日期:2012.10.5
an iterative synthesis of oligo-vinyl ethers, followed by a radical cascade to provide a family of hexahydro-2H-furo[3,4-b]pyrans. Our results for the radical cascade were consistent with either a direct 6-endo-trig addition of a vinyl radical onto the first vinyl ether function or an initial 5-exo-trig addition, followed by rearrangement to the more stable anomeric radical intermediate. In this report