53911-36-7Relevant academic research and scientific papers
Visible-Light-Driven C4-Selective Alkylation of Pyridinium Derivatives with Alkyl Bromides
Hong, Sungwoo,Jung, Sungwoo,Park, Seongjin,Shin, Sanghoon
supporting information, p. 11370 - 11375 (2020/07/21)
Reported herein is a general strategy for the photochemical cross-coupling between N-amidopyridinium salts and various alkyl bromides under photocatalyst-free conditions, granting facile access to various C4-alkylated pyridines. This approach exploits the intriguing photochemical activity of electron donor-acceptor (EDA) complexes between N-amidopyridinium salts and bromide, which provides a photoactive handle capable of generating silyl radicals and driving the alkylation process. The robustness of this protocol was further demonstrated by the late-stage functionalization of complex compounds under mild and metal-free conditions.
Functionalization of Pyridinium Derivatives with 1,4-Dihydropyridines Enabled by Photoinduced Charge Transfer
Hong, Sungwoo,Kim, Inwon,Park, Seongjin
supporting information, (2020/11/13)
By exploiting electron donor-acceptor (EDA) complexes between 1,4-dihydropyridines and N-amidopyridinium salts under visible light irradiation, we discovered that photoinduced intermolecular charge transfer induces a single-electron transfer event without requiring a photocatalyst for the facile functionalization of pyridines. The generality of this method is amenable to various types of 1,4-dihydropyridines radical precursors to generate structurally different radicals such as alkyl, acyl, and carbamoyl radicals, ultimately providing facile access to synthetically valuable C4-functionalized pyridines. A broad range of functional groups are well accommodated under mild and metal-free conditions, and the synthetic utility of the present method is showcased by the late-stage functionalization of a variety of biologically relevant pyridine-based compounds, pharmaceuticals, and peptide feedstocks.
Stereodivergent Synthesis of Alkenylpyridines via Pd/Cu Catalyzed C-H Alkenylation of Pyridinium Salts with Alkynes
Chen, Hua,Haiyan, Fu,Jiang, Weidong,Li, Ruixiang,Li, Shun,Li, Wenjing,Tang, Juan,Xu, Bin,Yuan, Maolin,Zheng, Xueli
supporting information, p. 7814 - 7819 (2020/11/03)
The first Pd/Cu catalyzed selective C2-alkenylation of pyridines with internal alkynes has been developed via the pyridinium salt activation strategy. Importantly, the configuration of the product alkenylpyridines could be tuned by the choice of the proper N-alkyl group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with good regio- and stereoselectivity. A plausible mechanism was proposed based on the Hammett study and KIE experiment.
C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
supporting information, p. 3990 - 3998 (2018/09/12)
An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
Impact of the use of sterically congested Ir(iii) complexes on the performance of light-emitting electrochemical cells
Hierlinger, Claus,Trzop, Elzbieta,Toupet, Lo?c,ávila, Jorge,La-Placa, Maria-Grazia,Bolink, Henk J.,Guerchais, Véronique,Zysman-Colman, Eli
supporting information, p. 6385 - 6397 (2018/07/05)
The synthesis, structural and optoelectronic characterization of a family of sterically congested cyclometalated cationic Ir(iii) complexes of the form [Ir(C^N)2(dtBubpy)]PF6 (with dtBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine and C^N = a cyclometalating ligand decorated at the 4-position of the pyridine ring and/or the 3-position of the phenyl ring with a range of sterically bulky substituents) are reported. This family of complexes is compared to the unsubstituted analogue complex R1 bearing 2-phenylpyridinato as cyclometalating ligand. The impact of sterically bulky substituents on the C^N ligands on both the solid state photophysics and light-emitting electrochemical cell (LEEC) device performance is investigated. X-ray diffraction analysis of complexes 1a, R2, 2a, and 1b show an increasing internuclear distance in the solid state, within these four complexes. Emission studies in solution and neat film show that the chosen substituents essentially do not impact the emission energy. The photoluminescence quantum yields (ΦPL) are in the same range (ΦPL ～ 25-31%), except for 1b, which shows a lower ΦPL of 12%. All complexes exhibit similar monoexponential emission lifetimes in the submicrosecond regime. LEECs based on R1, 1a, 1b and R2 were fabricated, showing yellow luminescence and moderate efficiencies and lifetimes. The arguably best performing LEEC device, showing the highest luminance (737 cd m-2), current efficiency (7.4 cd A-1) and EQE (2.6%), employed emitter 1a.
Spin-Center Shift-Enabled Direct Enantioselective α-Benzylation of Aldehydes with Alcohols
Nacsa, Eric D.,MacMillan, David W. C.
supporting information, p. 3322 - 3330 (2018/03/13)
Nature routinely engages alcohols as leaving groups, as DNA biosynthesis relies on the removal of water from ribonucleoside diphosphates by a radical-mediated "spin-center shift" (SCS) mechanism. Alcohols, however, remain underused as alkylating agents in synthetic chemistry due to their low reactivity in two-electron pathways. We report herein an enantioselective α-benzylation of aldehydes using alcohols as alkylating agents based on the mechanistic principle of spin-center shift. This strategy harnesses the dual activation modes of photoredox and organocatalysis, engaging the alcohol by SCS and capturing the resulting benzylic radical with a catalytically generated enamine. Mechanistic studies provide evidence for SCS as a key elementary step, identify the origins of competing reactions, and enable improvements in chemoselectivity by rational photocatalyst design.
Silver-Catalyzed Minisci Reactions Using Selectfluor as a Mild Oxidant
Galloway, Jordan D.,Mai, Duy N.,Baxter, Ryan D.
supporting information, p. 5772 - 5775 (2017/11/10)
A new method for silver-catalyzed Minisci reactions using Selectfluor as a mild oxidant is reported. Heteroarenes and quinones both participate in radical C-H alkylation and arylation from a variety of carboxylic and boronic acid radical precursors. Several oxidatively sensitive and highly reactive radical species are successful, providing structures that are challenging to access by other means.
ORGANIC COMPOUND AND ORGANIC LIGHT-EMITTING ELEMENT USING THE SAME
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, (2017/07/01)
PROBLEM TO BE SOLVED: To provide a compound which has an electron-donating property and is stable in the atmosphere. SOLUTION: The organic compound is represented by general formula [1] (where n represents an integer from 0 to 3 inclusive; R1 and R4 each represent an alkyl group or an aryl group selected from a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a phenanthrenyl group, a fluorenyl group, and a fluoranthenyl group; when R1 or R4 is an aryl group, the aryl group may further have an alkyl group; R2 and R3 each represent an alkyl group or an aryl group selected from a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a phenanthryl group, a fluorenyl group, and a fluoranthenyl group; when R2 or R3 is an aryl group, the aryl group may further have an alkyl group, a phenyl group, or a naphthyl group; when R1 and R4 are alkyl groups, R2 and R3 are aryl groups; and when R2 and R3 are alkyl groups, R1 and R4 are aryl groups). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
Lewis acid-catalyzed borono-minisci reactions of arylboronic acids and heterocycles
Biaco, Joyce L.,Jones, Savannah L.,Barker, Timothy J.
, p. 1687 - 1697 (2016/10/12)
A Lewis acid-catalyzed Minisci reaction between arylboronic acids and heterocycles has been developed. This radical-coupling reaction was demonstrated employing several different heterocycles as well as electron-rich arylboronic acids. Quinoline substrates afforded modest regioselectivity for substitution at the 4-position under the reaction conditions, in contrast to previously reported Br?nsted acid-mediated reactions with quinoline substrates that favored substitution at the 2-position.
ORGANOMETALLIC COMPLEX AND ORGANIC LIGHT-EMITTING ELEMENT USING THE COMPLEX
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Paragraph 0349; 0350, (2014/08/06)
Provided is an organic light-emitting element having high light-emitting efficiency and a long element lifetime, the organic light-emitting element including an anode, a cathode, and an organic compound layer placed between the anode and the cathode, in which: the organic compound layer includes an emission layer; the emission layer includes a host and a guest; the host is an aromatic hydrocarbon compound; the guest is an iridium complex of a specific structure; and a content of the host is 50 wt% or more with reference to the total amount of the constituent materials for the emission layer.
