14159-54-7Relevant articles and documents
Superacid-catalyzed reactions of olefinic pyrazines: An example of anti-markovnikov addition involving superelectrophiles
Zhang, Yiliang,Briski, Jason,Zhang, Yun,Rendy, Rendy,Klumpp, Douglas A.
, p. 2505 - 2508 (2005)
(Chemical Equation Presented) Olefinic pyrazines are found to react with benzene in CF3SO3H and give anti-Markovnikov-type addition products. We propose that this is caused by two effects: destabilization of the carbocationic interme
Iridium(III) Complexes Bearing a Formal Tetradentate Coordination Chelate: Structural Properties and Phosphorescence Fine-Tuned by Ancillaries
Yuan, Yi,Gnanasekaran, Premkumar,Chen, Yu-Wen,Lee, Gene-Hsiang,Ni, Shao-Fei,Lee, Chun-Sing,Chi, Yun
, p. 523 - 532 (2020)
Synthesis of the multidentate coordinated chelate N3C-H2, composed of a linked functional pyridyl pyrazole fragment plus a peripheral phenyl and pyridyl unit, was obtained using a multistep protocol. Preparation of Ir(III) metal complexes bearing a N3C chelate in the tridentate (κ3), tetradentate (κ4), and pentadentate (κ5) modes was executed en route from two nonemissive dimer intermediates [Ir(κ3-N3CH)Cl2]2 (1) and [Ir(κ4-N3C)Cl]2 (2). Next, a series of mononuclear Ir(III) complexes with the formulas [Ir(κ4-N3C)Cl(py)] (3), [Ir(κ4-N3C)Cl(dmap)] (4), [Ir(κ4-N3C)Cl(mpzH)] (5), and [Ir(κ4-N3C)Cl(dmpzH)] (6), as well as diiridium complexes [Ir2(κ5-N3C)(mpz)2(CO)(H)2] (7) and [Ir2(κ5-N3C)(dmpz)2(CO)(H)2] (8), were obtained upon treatment of dimer 2 with pyridine (py), 4-dimethylaminopyridine (dmap), 4-methylpyrazole (mpzH), and 3,5-dimethylpyrazole (dmpzH), respectively. These Ir(III) metal complexes were identified using spectroscopic methods and by X-ray crystallographic analysis of representative derivatives 3, 5, and 7. Their photophysical and electrochemical properties were investigated and confirmed by the theoretical simulations. Notably, green-emitting organic light-emitting diode (OLED) on the basis of Ir(III) complex 7 gives a maximum external quantum efficiency up to 25.1%. This result sheds light on the enormous potential of this tetradentate coordinated chelate in the development of highly efficient iridium complexes for OLED applications.
Mild Condition for the Deoxygenation of α-Heteroaryl-Substituted Methanol Derivatives
Meng, Na,Yu, Wensheng,Suzuki, Takao,Chen, Maofen,Qi, Zhiqi,Hu, Bin,Bao, Jianming,Debenham, John S.,Mazzola, Robert,Duffy, Joseph L.
, p. 5560 - 5567 (2021/05/04)
A mild condition via PPh3/I2/imidazole for the deoxygenation of substituted methanol derivatives has been identified. This metal-free process was found to proceed well on secondary or tertiary alcohols substituted with one or two heteroaryl groups, and it tolerates acid-sensitive heterocycles. This condition works for methanol derivatives substituted with 2-pyridyl, 4-pyridyl, or other heterocyclic groups, allowing the negative charge formed during the reaction to resonate to a nitrogen atom. Methanol derivatives substituted with 3-pyridyl or heterocyclic groups that do not allow the negative charge formed during the reaction to resonate to a nitrogen atom will not undergo deoxygenation under this condition.
Reductive activation and hydrofunctionalization of olefins by multiphoton tandem photoredox catalysis
Czyz, Milena L.,Taylor, Mitchell S.,Horngren, Tyra H.,Polyzos, Anastasios
, p. 5472 - 5480 (2021/06/01)
The conversion of olefin feedstocks to architecturally complex alkanes represents an important strategy in the expedient generation of valuable molecules for the chemical and life sciences. Synthetic approaches are reliant on the electrophilic activation of unactivated olefins, necessitating functionalization with nucleophiles. However, the reductive functionalization of unactivated and less activated olefins with electrophiles remains an ongoing challenge in synthetic chemistry. Here, we report the nucleophilic activation of inert styrenes through a photoinduced direct single electron reduction to the corresponding nucleophilic radical anion. Central to this approach is the multiphoton tandem photoredox cycle of the iridium photocatalyst [Ir(ppy)2(dtbbpy)] PF6, which triggers in situ formation of a high-energy photoreductant that selectively reduces styrene olefinic π bonds to radical anions without stoichiometric reductants or dissolving metals. This mild strategy enables the chemoselective reduction and hydrofunctionalization of styrenes to furnish valuable alkane and tertiary alcohol derivatives. Mechanistic studies support the formation of a styrene olefinic radical anion intermediate and a Birch-type reduction involving two sequential single electron transfers. Overall, this complementary mode of olefin activation achieves the hydrofunctionalization of less activated alkenes with electrophiles, adding value to abundant olefins as valuable building blocks in modern synthetic protocols.
C2-selective alkylation of pyridines by rhodium–aluminum complexes
Aso, Koki,Hara, Naofumi,Li, Qiao-Zhi,Nakao, Yoshiaki,Sakaki, Shigeyoshi
supporting information, (2021/08/06)
A C2- and mono-selective alkylation of various pyridines and azines with unactivated alkenes and vinylarenes using a heterobimetallic Rh–Al catalyst is reported. The use of aliphatic alkenes exclusively affords the linear alkylation products, while vinylarenes mainly afford branched alkylation products. The details of the reaction mechanism are revealed by DFT calculations: the reductive elimination of the products is rate-determining, which is consistent with the experimental results. The origin of the linear/branched selectivity is elucidated based on deformation/interaction analysis.
Organic Electroluminescent Materials and Devices
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Paragraph 0164; 0183-0187, (2020/08/25)
A compound comprising a hexadentate ligand of Formula I coordinated to a metal selected from the group consisting of iridium, rhodium, and osmium wherein rings A, D, and E are independently a 5-membered or 6-membered heteroaryl ring, or a 6-membered aryl
Photoenzymatic Hydrogenation of Heteroaromatic Olefins Using ‘Ene’-Reductases with Photoredox Catalysts
Biegasiewicz, Kyle F.,Black, Michael J.,Chung, Megan M.,Hyster, Todd K.,Meichan, Andrew J.,Nakano, Yuji,Sandoval, Braddock A.,Zhu, Tianyu
supporting information, p. 10484 - 10488 (2020/04/29)
Flavin-dependent ‘ene’-reductases (EREDs) are highly selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to the corresponding neutral benzylic radical in solution. DFT calculations reveal this radical to be “dynamically stable”, suggesting it is sufficiently long-lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer. This reduction mechanism is distinct from the native one, highlighting the opportunity to expand the synthetic capabilities of existing enzyme platforms by exploiting new mechanistic models.
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES
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Paragraph 0155; 0158-0159, (2019/11/19)
A compound having the formula Ir(LA)(LB), where LA has a structure of Formula I and LB is a bidentate ligand is disclosed. In the structure of Formula I, rings A, B, C, and D are each independently 5- or 6-membe
Rhodium Complexes Bearing PAlP Pincer Ligands
Hara, Naofumi,Saito, Teruhiko,Semba, Kazuhiko,Kuriakose, Nishamol,Zheng, Hong,Sakaki, Shigeyoshi,Nakao, Yoshiaki
supporting information, p. 7070 - 7073 (2018/06/01)
We report rhodium complexes bearing PAlP pincer ligands with an X-type aluminyl moiety. IR spectroscopy and single-crystal X-ray diffraction analysis of a carbonyl complex exhibit the considerable σ-donating ability of the aluminyl ligand, whose Lewis acidity is confirmed through coordination of pyridine to the aluminum center. The X-type PAlP-Rh complexes catalyze C2-selective monoalkylation of pyridine with alkenes.
Iron-Catalyzed Aerobic Oxidation of (Alkyl)(aryl)azinylmethanes
Sterckx, Hans,Sambiagio, Carlo,Lemière, Filip,Tehrani, Kourosch Abbaspour,Maes, Bert U. W.
supporting information, p. 1564 - 1570 (2017/08/11)
An iron-catalyzed aerobic oxidation of (alkyl)(aryl)azinylmethanes has been developed leading to tertiary alcohols in moderate to good yields. Hock rearrangement was identified as a major side reaction leading to a complex mixture of undesired products. Addition of thiourea sometimes allows inhibiting this side reaction and steers the reaction towards the desired products.
