37696-03-0Relevant articles and documents
Biogenic palladium nanoclusters supported on hybrid nanocomposite 2-hydroxypropyl-β-cyclodextrin/alginate as a recyclable catalyst in aqueous medium
Nguyen, Thanh-Danh,Vo, Thanh-Truc,Nguyen, Cao-Hien,Doan, Van-Dat,Dang, Chi-Hien
, p. 927 - 935 (2019)
This paper develops a simple and green process of synthesizing palladium nanoclusters (PdNCs) capped on the hybrid nanocomposite based on biodegradable polysaccharides, 2-hydroxypropyl-β-cyclodextrin (HPCD) and alginate (Alg) through an ionotropic gelation mechanism. PdNCs were biosynthesized from aqueous extract of Burdock root (BR), Arctium lappa. The nanocomposite PdNCs/HPCD/Alg was characterized by techniques like UV–Vis, FTIR, EDX, FESEM, TEM, HR-TEM and TG-DTA. The crystal palladium nanoparticles were found to distribute in cluster shape with a size of 4–10 nm. EDX data showed that average amount of palladium capped on the hybrid nanocomposite was approx. 4.7% (w/w). PdNCs/HPCD/Alg exhibited highly catalytic activity for degradation of pollutants including 4-nitrophenol, methyl orange and rhodamine B in wastewater and leaching mechanism of the nanocatalyst was showed. In particular, the nanocomposite showed excellent aqueous-phase catalytic performance for free-triphenylphosphine Sonogashira cross-coupling reaction. The nanocatalyst could be efficiently reused without much compromising with its activity.
A facile protocol for copper-free palladium-catalyzed Sonogashira coupling in aqueous media
Jung, Da-Young,Park, Soo Youl,Kim, Seung-Hoi
supporting information, p. 110 - 116 (2021/11/09)
The combination of a readily available palladium catalyst and an eco-friendly basic aqueous solution of room-temperature ionic liquid, choline hydroxide (ChOH), was used in a facile protocol alternative to the Sonogashira coupling reaction, alkynylation of aryl halides in the absence of a copper cocatalyst and an external base. The dual nature of ChOH to act as a base and a green solvent played a crucial role in the catalytic cycle. The coupling reaction progressed efficiently to form a Csp-Csp2 bond under the identified conditions although the reaction outcome depended significantly on the substrates.
Cascade Process for Direct Transformation of Aldehydes (RCHO) to Nitriles (RCN) Using Inorganic Reagents NH2OH/Na2CO3/SO2F2 in DMSO
Fang, Wan-Yin,Qin, Hua-Li
, p. 5803 - 5812 (2019/05/14)
A simple, mild, and practical process for direct conversion of aldehydes to nitriles was developed feathering a wide substrate scope and great functional group tolerability (52 examples, over 90% yield in most cases) using inorganic reagents (NH2OH/Na2CO3/SO2F2) in DMSO. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable nitriles in a pot, atom, and step-economical manner without transition metals. This protocol will serve as a robust tool for the installation of cyano-moieties to complicated molecules.
DBU-Mediated Efficient Synthesis of Diaryl Ethynes and Enynes from 1,1-Dibromoalkenes at Room Temperature
Thummala, Yadagiri,Morri, Ashok K.,Karunakar, Galla V.,Doddi, Venkata Ramana
supporting information, p. 6280 - 6285 (2018/11/23)
The reaction of 1,1-dibromoalkenes and aryl iodides in the presence of DBU and a PdII/CuI catalytic system afforded diaryl alkynes and enynes at ambient temperature. Control experiments demonstrated the essential ligand role of DBU i
Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles
Lasányi, Dániel,Mészáros, ádám,Novák, Zoltán,Tolnai, Gergely L.
, p. 8281 - 8291 (2018/06/11)
For the synthesis of unsymmetrical acetylenes, a Sonogashira coupling-deprotection-Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic acid, an inexpensive nontoxic compound, was used to promote the selective desilylation. This method enables the efficient synthesis of unsymmetric acetylenes with other silylated functional groups present. Further possibilities of the method were explored by synthesis of heterocycles.
A phosphine-free, atom-efficient cross-coupling of aryl iodides with triarylindiums or trialkynylindiums catalyzed by immobilization of palladium(0) in MCM-41
Lei, Zhiwei,Liu, Haiyi,Cai, Mingzhong
, p. 54 - 63 (2017/10/25)
The first phosphine-free heterogeneous atom-efficient cross-coupling reaction of aryl iodides with triarylindiums or trialkynylindiums was achieved in THF at 68 °C by using 1 mol% of MCM-41-immobilized palladium(0)-Schiff base complex [MCM-41-N,N-Pd(0)] as catalyst, yielding a variety of unsymmetrical biaryls and arylalkynes in good to excellent yields. The heterogeneous palladium(0) catalyst could easily be prepared via a simple procedure from commercially readily available reagents, and recovered by filtration of the reaction solution and recycled at least 10 times without significant loss of activity.
External oxidant-free cross-coupling of arylcopper and alkynylcopper reagents leading to arylalkyne
Wang, Sheng,Min, Yaosen,Zhang, Xiaowei,Xi, Chanjuan
, p. 28308 - 28312 (2017/07/07)
External oxidant-free oxidative cross-coupling between arylcopper and alkynylcopper has been performed, which provides a new way for the formation of arylalkyne with high selectivity.
Nano palladium supported on high-surface-area metal-organic framework MIL-101: An efficient catalyst for Sonogashira coupling of aryl and heteroaryl bromides with alkynes
Annapurna, Manne,Parsharamulu,Vishnuvardhan Reddy,Suresh,Likhar, Pravin R.,Lakshmi Kantam, Mannepalli
, p. 234 - 239 (2015/03/30)
Palladium nanoparticle-incorporated metal-organic framework MIL-101 (Pd/MIL-101) was successfully synthesized and characterized using X-ray diffraction, nitrogen physisorption, X-ray photoelectron, UV-visible and infrared spectroscopies, and transmission electron microscopy. The characterization techniques confirmed high porosity and high surface area of MIL-101 and high stability of nano-size palladium particles. Pd/MIL-101 nanocomposite was investigated for the Sonogashira cross-coupling reaction of aryl and heteroaryl bromides with various alkynes under copper-free conditions. The reusability of the catalyst was tested for up to four cycles without any significant loss in catalytic activity.
Melamine-based microporous network polymer supported palladium nanoparticles: A stable and efficient catalyst for the sonogashira coupling reaction in water
Shunmughanathan, Murugesan,Puthiaraj, Pillaiyar,Pitchumani, Kasi
, p. 666 - 673 (2015/03/05)
A template consisting of a melamine-based microporous polymer network was synthesized and utilized as a solid support to stabilize palladium nanoparticles; the resulting Pd/SNW1 material showed good catalytic activity in copper-free Sonogashira coupling in water. Various aryl iodides were efficiently coupled with arylacetylenes under very low catalyst loadings in an environmentally benign medium. Hot filtration tests confirmed the heterogeneity of the catalyst, which was reused under the optimized conditions without any significant change in its activity. This simple preparation of the catalyst, the stability of the catalyst, product selectivity, and easy recovery and regeneration indicate the possible utilization of this catalytic system in a multitude of catalyzed reactions and industrial processes. Networking possibilities: A template consisting of melamine-based microporous polymer network is synthesized and utilized as a solid support to stabilize palladium nanoparticles; the resulting Pd/SNW1 material shows good catalytic activity in copper-free Sonogashira coupling in water. Various aryl iodides are efficiently coupled with arylacetylenes under very low catalyst loadings in an environmentally benign medium.
Ligand Control of E/Z Selectivity in Nickel-Catalyzed Transfer Hydrogenative Alkyne Semireduction
Richmond, Edward,Moran, Joseph
, p. 6922 - 6929 (2015/10/05)
A nickel-catalyzed transfer hydrogenative alkyne semireduction protocol that can be applied to both internal and terminal alkynes using formic acid and Zn as the terminal reductants has been developed. In the case of internal alkynes, the (E)- or (Z)-olefin isomer can be accessed selectively under the same reaction conditions by judicious inclusion of a triphos ligand.
