25739-23-5Relevant articles and documents
Microwave-assisted copper catalyzed coupling reaction of aryl halides with terminal alkynes
Wang, Jin-Xian,Liu, Zhanxiang,Hu, Yulai,Wei, Bangguo,Kang, Liqin
, p. 1937 - 1945 (2002)
Coupling reaction of aryl halides with terminal alkynes using catalyst system of copper (I)-triphenylphosphine proceeds efficiently in the presence of potassium carbonate under microwave irradiation to give the corresponding unsymmetrical acetylenes in go
Hybrid hydrogels loaded with palladium nanoparticles – Catalysts for environmentally-friendly Sonogashira and Heck cross-coupling reactions
Slavik, Petr,Smith, David K.
, (2020/07/07)
Palladium nanoparticles (PdNPs) were encapsulated within hybrid hydrogels made from an acylhydrazide-functionalised 1,3:2,4-dibenzylidene sorbitol (DBS-CONHNH2) low-molecular-weight gelator (LMWG) combined with agarose polymer gelator via in situ reduction of Pd(II). These heterogeneous gel-phase catalysts were successfully applied for copper-, amine- and phosphine-free Sonogashira cross-coupling reactions under environmentally-friendly conditions without the need for inert atmosphere reaction conditions. The PdNP-loaded gel was reused in Sonogashira couplings up to at least five times with no adverse effect on yield. The performance of solvated PdNP-loaded gel catalysts was compared with the dried xerogels. The xerogels can be used at higher temperatures, enhancing reaction kinetics albeit lowering reaction selectivity, but unlike the solvated gels, were unable to be easily recycled and reused. The PdNP-loaded gels also had good activity in Heck reactions, and although longer reaction times or higher temperatures were required than for the Sonogashira reaction, the reaction conditions were mild for a Heck coupling. In summary, we demonstrate a ‘waste-to-wealth’ methodology in which Pd(II) ‘waste’ is converted into a valuable gel-phase catalyst that can be used for green Sonogashira and Heck cross-coupling reactions.
Magnetic Cu–Schiff base complex with an ionic tail as a recyclable bifunctional catalyst for base/Pd-free Sonogashira coupling reaction
Nasseri, Mohammad Ali,Rezazadeh, Zinat,Kazemnejadi, Milad,Allahresani, Ali
, p. 2693 - 2705 (2019/07/23)
Abstract: A Cu(II)–Schiff base complex containing imidazolium ionic phase was prepared and decorated on γ-Fe2O3 magnetic nanoparticles (γ-Fe2O3@Cu(II)IL-SB) and found to be an efficient catalyst for the Pd- and base-free Sonogashira coupling reaction. The heterogeneous catalyst was characterized by FTIR spectroscopy, UV–visible spectroscopy, FE-SEM, TEM, XRD spectroscopy, EDX spectroscopy, VSM, ICP spectroscopy, and atomic absorption spectroscopy. The coupling reactions were performed using the catalyst under mild and base-free conditions, and high-to-excellent yields were obtained for a variety of substrates. The catalyst demonstrates a dual-functionality arising from metal sites and imidazolium moieties and that the later plays a base role. Reusability and stability of γ-Fe2O3@Cu(II)IL-SB were studied several times, which can be reused up to eight consecutive runs with at least reduction in catalytic activity. Also, the mechanism of this bifunctional catalytic system was thoroughly investigated. Graphic abstract: A new and efficient method has been developed for the base- and Pd-free Sonogashira cross-coupling reactions of aryl halides with phenyl acetylene using a bifunctional γ-Fe2O3@Cu(II)IL-SB catalyst with imidazolium moiety under mild conditions[Figure not available: see fulltext.].
