5069-26-1Relevant articles and documents
Metalated Porous Phenanthroline-Based Polymers as Efficient Heterogeneous Catalysts for Regioselective C?H Activation of Heteroarenes
Tang, Yongquan,Dai, Zhifeng,Wang, Sai,Chen, Fang,Meng, Xiangju,Xiao, Feng-Shou
, p. 2469 - 2474 (2021/08/06)
Direct C?H bond activation of heterocycles as a step-economical and environmentally friendly approach to build the heterobiaryls motifs is highly attractive, but it still has a challenge to design and prepare a cheap and regioselective heterogeneous catal
Programmed Synthesis of Tetra-Aryl Thiophenes with Stepwise, Ester-Controlled Regioselectivity
Messina, Cynthia,Ottenwaelder, Xavier,Forgione, Pat
supporting information, p. 7348 - 7352 (2021/10/01)
Herein, we report a modular synthetic route to access tetra-arylated thiophene compounds with four different substituents with programmed chemical control provided by an ester activating/directing group. This method enables the functionalization of indivi
Light-Switchable and Self-Healable Polymer Electrolytes Based on Dynamic Diarylethene and Metal-Ion Coordination
Nie, Hui,Schauser, Nicole S.,Self, Jeffrey L.,Tabassum, Tarnuma,Oh, Saejin,Geng, Zhishuai,Jones, Seamus D.,Zayas, Manuel S.,Reynolds, Veronica G.,Chabinyc, Michael L.,Hawker, Craig J.,Han, Songi,Bates, Christopher M.,Segalman, Rachel A.,Read De Alaniz, Javier
supporting information, p. 1562 - 1569 (2021/02/01)
Self-healing polymer electrolytes are reported with light-switchable conductivity based on dynamic N-donor ligand-containing diarylethene (DAE) and multivalent Ni2+ metal-ion coordination. Specifically, a polystyrene polymer grafted with poly(ethylene glycol-r-DAE)acrylate copolymer side chains was effectively cross-linked with nickel(II) bis(trifluoromethanesulfonimide) (Ni(TFSI)2) salts to form a dynamic network capable of self-healing with fast exchange kinetics under mild conditions. Furthermore, as a photoswitching compound, the DAE undergoes a reversible structural and electronic rearrangement that changes the binding strength of the DAE-Ni2+ complex under irradiation. This can be observed in the DAE-containing polymer electrolyte where irradiation with UV light triggers an increase in the resistance of solid films, which can be recovered with subsequent visible light irradiation. The increase in resistance under UV light irradiation indicates a decrease in ion mobility after photoswitching, which is consistent with the stronger binding strength of ring-closed DAE isomers with Ni2+. 1H-15N heteronuclear multiple-bond correlation nuclear magnetic resonance (HMBC NMR) spectroscopy, continuous wave electron paramagnetic resonance (cw EPR) spectroscopy, and density functional theory (DFT) calculations confirm the increase in binding strength between ring-closed DAE with metals. Rheological and in situ ion conductivity measurements show that these polymer electrolytes efficiently heal to recover their mechanical properties and ion conductivity after damage, illustrating potential applications in smart electronics.
Nickel-catalyzed and Li-mediated regiospecific C-H arylation of benzothiophenes
Canivet, Jér?me,Grousset, Léonie,Hisler, Ga?lle,Mohr, Yorck,Quadrelli, Elsje Alessandra,Roux, Yoann,Wisser, Florian M.
, p. 3155 - 3161 (2020/06/19)
A nickel-based catalytic system for the regiospecific C2-H arylation of benzothiophene has been established. NiCl2(bpy) is used as a catalyst in combination with LiHMDS as a base in dioxane. The catalytic system is applicable to a variety of functionalized benzothiophenes, as well as other heteroarenes including thiophene, benzodithiophene, benzofuran and selenophene in combination with iodo aryl electrophiles. The role of LiHMDS as a uniquely potent base and a postulated mechanism are discussed. The applicability of this system is finally demonstrated for the synthesis of an intermediate of an active pharmaceutical ingredient.
Well-Defined Palladium N-Heterocyclic Carbene Complexes: Direct C-H Bond Arylation of Heteroarenes
Kumar, Anuj,Kumar, Manoj,Verma, Akhilesh K.
, p. 13983 - 13996 (2020/11/20)
A series of palladium N-heterocyclic carbene (NHC) complexes of type trans-{(NHC)PdCl2L} (L = C5H5N, 3-ClC5H4N, and PPh3) (3-5) have been developed as efficient precatalysts for direct C-H bond arylation of various heteroarenes. In particular, an in situ generated new NHC ligand derived from {1,3-di-(2,6-diethylphenyl)acenaphtho[1,2-d] imidazolium} chloride (2) is used for the stabilization of the palladium metal center. Among the screened palladium precatalysts (3-5), the most active PEPPSI themed complex (3) was successfully employed toward direct C-H bond arylation of various heteroarenes and aryl bromides. A range of functional groups on aryl bromides as well as on heteroarenes sustained throughout the standard reaction conditions for easy access of various arylated heterocyclic compounds. Significantly, the utility of the protocol was demonstrated by the effective synthesis of a precursor of raloxifene, a selective estrogen receptor modulator.
A Convoluted Polyvinylpyridine-Palladium Catalyst for Suzuki-Miyaura Coupling and C?H Arylation
Ohno, Aya,Sato, Takuma,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
supporting information, p. 4687 - 4698 (2020/09/07)
The development of highly active and reusable supported catalysts for Suzuki-Miyaura coupling and catalytic C?H arylation is important for fundamental and applied chemistry, with these reactions being used to produce medical compounds and functional materials. Herein, we found that a mesoporous composite made of a linear poly(4-vinylpyridine) and tetrachloropalladate acted as a dual-mode catalyst for a variety of cross-coupling reactions, with both Pd nanoparticles and a Pd complex catalyst being observed under different conditions. The polyvinylpyridine-palladium composite 1 was readily prepared via the molecular convolution of poly(4-vinylpyridine) and sodium tetrachloropalladate to provide a hardly soluble polymer-metal composite. The Suzuki-Miyaura coupling and the C?H arylation of aryl chlorides and bromides with arylboronic acids, thiophenes, furans, benzene, and anisole proceeded in the presence of 0.004 mol% (40 mol ppm) to 1 mol% Pd of 1 to afford the corresponding coupling products in high yields. Furthermore, the catalyst was reused without an appreciable loss of activity. Pharmaceutical compounds and functional materials were synthesized via the coupling reactions. N2 gas adsorption/desorption analysis indicated that the catalyst had a mesoporous nature, which played a crucial role in the catalysis. In the Suzuki-Miyaura couplings, in situ generated palladium nanoparticles in the polymer matrix were catalytically active, while a polymeric Pd(II) complex was crucial in the C?H arylations. These catalytic species were investigated via XAFS, XPS, far-infrared absorption, and Raman spectroscopies, as well as DFT calculations. (Figure presented.).
Light-Controllable Ionic Conductivity in a Polymeric Ionic Liquid
Dolinski, Neil D.,Hawker, Craig J.,Hu, Jerry,Nie, Hui,Read de Alaniz, Javier,Schauser, Nicole S.,Segalman, Rachel A.
supporting information, p. 5123 - 5128 (2020/02/11)
Polymeric ionic liquids (PILs) have attracted considerable attention as electrolytes with high stability and mechanical durability. Light-responsive materials are enabling for a variety of future technologies owing to their remote and noninvasive manipula
Palladium-Catalyzed Methylation of Aryl, Heteroaryl, and Vinyl Boronate Esters
Haydl, Alexander M.,Hartwig, John F.
supporting information, p. 1337 - 1341 (2019/02/26)
A method for the direct methylation of aryl, heteroaryl, and vinyl boronate esters is reported, involving the reaction of iodomethane with aryl-, heteroaryl-, and vinylboronate esters catalyzed by palladium and PtBu2Me. This transformation occurs with a remarkably broad scope and is suitable for late-stage derivatization of biologically active compounds via the boronate esters. The unique capabilities of this method are demonstrated by combining carbon-boron bond-forming reactions with palladium-catalyzed methylation in a tandem transformation.
Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters
He, Zhi-Tao,Li, Haoquan,Haydl, Alexander M.,Whiteker, Gregory T.,Hartwig, John F.
supporting information, p. 17197 - 17202 (2018/12/14)
A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C-H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C-H bonds and is illustrated by late-stage methylation of four medicinally active compounds. In addition, reaction on a 200 mmol scale demonstrates reliability of this method. Mechanistic studies show that the reaction occurs by a slow release of methyl iodide by reaction of PO(OMe)3 with iodide catalyst, rather than the typical direct oxidative addition to a metal center. The low concentration of the reactive electrophile enables selective reaction with an arylcopper intermediate, rather than nucleophilic groups on the arylboronate, and binding of tert-butoxide to the boronate inhibits reaction of the electrophile with the tert-butoxide activator to form methyl ether.
Accessing Heterobiaryls through Transition-Metal-Free C-H Functionalization
Banik, Ananya,Paira, Rupankar,Shaw, Bikash Kumar,Vijaykumar, Gonela,Mandal, Swadhin K.
, p. 3236 - 3244 (2018/03/23)
Herein we report a transition-metal-free synthetic protocol for heterobiaryls, one of the most important pharmacophores in the modern drug industry, employing a new multidonor phenalenyl (PLY)-based ligand. The current procedure offers a wide substrate scope (24 examples) with a low catalyst loading resulting in an excellent product yield (up to 95%). The reaction mechanism involves a single electron transfer (SET) from a phenalenyl-based radical to generate a reactive heteroaryl radical. To establish the mechanism, we have isolated the catalytically active SET initiator, characterizing by a magnetic study.
