151665-75-7Relevant academic research and scientific papers
Dithiocarbamates: Reagents for the Removal of Transition Metals from Organic Reaction Media
Gallagher, William P.,Vo, Anh
, p. 1369 - 1373 (2015)
Dithiocarbamates (DTCs) are ligands known to chelate with Cu and other transition metals to form insoluble complexes. Wastewater treatment protocols have utilized DTCs to remove trace (ppb) metals from waste streams. We have extended the applicability of DTCs to a protocol that readily enables control of the residual Cu in isolated material in a quick and cost-effective manner. Formation of the chelate complex typically results in purging of Cu and a variety of other metals in an array of reaction media to ≤10 ppm. Furthermore, the simplicity of the method makes it very attractive for large-scale applications late in a synthetic sequence because of the low toxicity and efficient removal of the metal complex by filtration.
Palladium Immobilized on 2,2′-Dipyridyl-Based Hypercrosslinked Polymers as a Heterogeneous Catalyst for Suzuki–Miyaura Reaction and Heck Reaction
Liu, Cijie,Xu, Wei,Xiang, Dexuan,Luo, Qionglin,Zeng, Shunqin,Zheng, Lijuan,Tan, Yujie,Ouyang, Yuejun,Lin, Hongwei
, p. 2558 - 2565 (2020/03/23)
Abstract: 2,2′-Bipyridine was successfully integrated into the skeleton of hypercrosslinked polymers networks (HCPs-bipy) via Friedel–Crafts reaction and Scholl coupling reaction, and PdCl2 was locked in this network polymers by coordination with pyridine motif. The preparation of HCPs-bipy has the advantages of low cost, mild conditions, easy separation and high yield. FT-IR, TGA, N2 sorption, ICP, XPS, SEM, EDX and TEM was employed to characterize the structure and composition of the heterogeneous catalysts. The result indicates that HCPs-bipy-Pd possess high specific surface areas, large microporous volume, thermal stability, and highly dispersion of palladium species. HCPs-bipy-Pd can be applied in Suzuki–Miyaura reactions and Heck reactions as robust heterogeneous catalyst to afford high yield. The reusability test demonstrates that HCPs-bipy-Pd could be recovered and reused for at least five times without losing catalytic activity. Graphic Abstract: [Figure not available: see fulltext.].
Sterically Controlled Late-Stage C-H Alkynylation of Arenes
Mondal, Arup,Chen, Hao,Fl?mig, Lea,Wedi, Philipp,Van Gemmeren, Manuel
supporting information, p. 18662 - 18667 (2019/11/28)
Phenylacetylenes are key structural motifs in organic chemistry, which find widespread applications in bioactive molecules, synthetic intermediates, functional materials, and reagents. These molecules are typically prepared from prefunctionalized starting materials, e.g. using the Sonogashira coupling, or using directing group-based C-H activation strategies. While highly efficient, these approaches remain limited by their inherent selectivities for specific regioisomers. Herein we present a complementary approach based on an arene-limited nondirected C-H activation. The reaction is predominantly controlled by steric rather than electronic factors and thereby gives access to a complementary product spectrum with respect to traditional methods. A broad scope as well as the suitability of this protocol for late-stage functionalization are demonstrated.
Palladium catalyst immobilized on functionalized microporous organic polymers for C-C coupling reactions
Xu, Wei,Liu, Cijie,Xiang, Dexuan,Luo, Qionglin,Shu, You,Lin, Hongwei,Hu, Yangjian,Zhang, Zaixing,Ouyang, Yuejun
, p. 34595 - 34600 (2019/11/11)
Two microporous organic polymer immobilized palladium (MOP-Pd) catalysts were prepared from benzene and 1,10-phenanthroline by Scholl coupling reaction and Friedel-Crafts reaction, respectively. The structure and composition of the catalyst were characterized by FT-IR, TGA, N2 sorption, SEM, TEM, ICP-AES and XPS. MOP-Pd catalysts were found to possess high specific surface areas, large pore volume and low skeletal bone density. Moreover, the immobilized catalyst also had advantages, such as readily available raw materials, chemical and thermal stability, and low synthetic cost. The Pd catalyst is an effective heterogeneous catalyst for carbon-carbon (C-C) coupling reactions, such as the Heck reaction and Suzuki-Miyaura reaction, affording good to high yields. In these reactions, the catalyst was easily recovered and reused five times without significant activity loss.
Ligand-accelerated non-directed C-H functionalization of arenes
Wang, Peng,Verma, Pritha,Xia, Guoqin,Shi, Jun,Qiao, Jennifer X.,Tao, Shiwei,Cheng, Peter T. W.,Poss, Michael A.,Farmer, Marcus E.,Yeung, Kap-Sun,Yu, Jin-Quan
, p. 489 - 493 (2017/11/28)
The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.
S,O-Ligand-Promoted Palladium-Catalyzed C-H Functionalization Reactions of Nondirected Arenes
Naksomboon, Kananat,Valderas, Carolina,Gómez-Martínez, Melania,álvarez-Casao, Yolanda,Fernández-Ibá?ez, M. ángeles
, p. 6342 - 6346 (2017/09/15)
Pd(II)-catalyzed C-H functionalization of nondirected arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C-H olefination reaction of electron-rich and electron-poor arenes. This methodology is operationally simple, scalable, and can be used in late-stage functionalization of complex molecules. The broad applicability of this catalyst has been showcased in other transformations such as Pd(II)-catalyzed C-H acetoxylation and allylation reactions.
Chiral Cyclopentadienyl Iridium(III) Complexes Promote Enantioselective Cycloisomerizations Giving Fused Cyclopropanes
Dieckmann, Michael,Jang, Yun-Suk,Cramer, Nicolai
supporting information, p. 12149 - 12152 (2015/10/12)
The cyclopentadienyl (Cp) group is a very important ligand for many transition-metal complexes which have been applied in catalysis. The availability of chiral cyclopentadienyl ligands (Cpx) lags behind other ligand classes, thus hampering the investigation of enantioselective processes. We report a library of chiral CpxIrIII complexes equipped with an atropchiral Cp scaffold. A robust complexation procedure reliably provides CpxIrIII complexes with tunable counterions. In a proof-of-concept application, the iodide-bearing members are shown to be highly selective for enyne cycloisomerization reactions. The dehydropiperidine-fused cyclopropane products are formed in good yields and enantioselectivities.
Palladium nanoparticles stabilized by metal-carbon covalent bond: An efficient and reusable nanocatalyst in cross-coupling reactions
Ganapathy, Dhandapani,Sekar, Govindasamy
, p. 50 - 54 (2013/07/26)
Palladium nanoparticles stabilized by PdC(binaphthyl) covalent bonds have been designed and synthesized. This new class of Pd nanoparticles was efficiently used as reusable catalysts for CC bond forming Heck, Suzuki-Miyaura and Sonogashira cross coupling reactions with high turnover. Even after the several catalytic cycles the Pd NPs had the same reactivity and particle size without any apparent agglomerization.
