612-96-4Relevant articles and documents
Substrate-Tuned Domino Annulation for Selective Synthesis of Poly-substituted Benzo[ f]imidazo[2,1- a][2,7]naphthyridines and 3-Azaheterocyclic Substituted 2-Arylquinolines
Ying, Zhimin,Cen, Jie,Luo, Feng,Wu, You,Liu, Shuangrong,Chen, Wenteng,Shao, Jiaan,Yu, Yongping
, p. 4747 - 4755 (2021)
A domino annulation/oxidation of heterocyclic ketene aminals (HKAs) and 2-aminochalcones has been developed for the selective synthesis of poly-substituted benzo[f]imidazo[2,1-a][2,7]naphthyridines and 3-azaheterocyclic substituted 2-arylquinolines. These reactions proceed well under mild conditions without any additives. Plausible mechanisms for such a polycyclic ring system assembly were also proposed. Moreover, benzo[f]imidazo[2,1-a][2,7]naphthyridine 3g displayed a fluorescence effect, demonstrating the potential applications in organic optical materials.
Furfuryl vinyl ethers in [4+2]-cycloaddition reactions
Oparina,Vysotskaya,Stepanov,Ushakov,Apartsin,Gusarova,Trofimov
, (2017)
For the first time [4+2]-cycloaddition reactions were carried out between furfuryl vinyl ethers and typical dienophiles and heterodienes proceeding in uncatalyzed conditions and resulting in previously unknown heterocyclic systems containing either free v
Enantioselective Dearomative [3 + 2] Umpolung Annulation of N-Heteroarenes with Alkynes
Cui, Bing-Hui,Huang, Wen-Yu,Jia, Yi-Xia,Liang, Ren-Xiao,Liu, Hang,Liu, Jia-Liang,Wang, Qiang,Yang, Peng,Zhang, Xiao-Dong,Zhang, Yue-Yuan
, p. 1087 - 1093 (2022/02/09)
Enantioselective [3 + 2] annulation of N-heteroarenes with alkynes has been developed via a cobalt-catalyzed dearomative umpolung strategy in the presence of chiral ligand and reducing reagent. A variety of electron-deficient N-heteroarenes, including qui
Dehydrogenation of N-Heterocyclic Compounds Using H2O2 and Mediated by Polar Solvents
Llopis, Natalia,Gisbert, Patricia,Baeza, Alejandro,Correa-Campillo, Jara
, p. 1205 - 1210 (2022/02/25)
The oxidative dehydrogenation of N-heterocyclic compounds by using H2O2 as oxidant in combination with polar solvents such as 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and H2O is described. Among these two solvents, the best yields for the heteroaromatic compounds were generally achieved in HFIP. However, it is remarkable, that the use of a non toxic solvent such as H2O gave such good yields. Furthermore, the procedure was implemented in larger-scale and HFIP was distilled from the reaction mixture and reused (up to 5 cycles) without a significant detriment in the reaction outcome. (Figure presented.).
Evaluation of P-bridged biaryl phosphine ligands in palladium-catalysed Suzuki-Miyaura cross-coupling reactions
Holzapfel, Cedric W.,Lamola, Jairus L.,Maumela, Munaka Christopher,Moshapo, Paseka T.
, p. 26883 - 26891 (2021/08/17)
A family of biaryl phosphacyclic ligands derived from phobane and phosphatrioxa-adamantane frameworks is described. The rigid biaryl phosphacycles are efficient for Suzuki-Miyaura cross-coupling of aryl bromides and chlorides. In particular, coupling reactions of the challenging sterically hindered and heterocyclic substrates were viable at room temperature.
2-Phosphinoimidazole Ligands: N-H NHC or P-N Coordination Complexes in Palladium-Catalyzed Suzuki-Miyaura Reactions of Aryl Chlorides
Martinez, Erin E.,Larson, Alexandra J. S.,Fuller, Sydney K.,Petersen, Kathryn M.,Smith, Stacey J.,Michaelis, David J.
supporting information, p. 1560 - 1564 (2021/05/29)
We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki-Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P-N coordinated and N-H NHC forms of ligand. Our studies suggest that the N-H NHC form may be important for high catalytic activity in Suzuki-Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.
Designing biaryl phosphacyclic ligands: their characterization and evaluation in palladium-catalyzed Suzuki-Miyaura reactions of aryl bromides and chlorides
Holzapfel, Cedric W.,Lamola, Jairus L.,Maumela, Munaka Christopher,Moshapo, Paseka T.
, (2021/12/22)
Efficient palladium catalyst systems based on the combination of bench stable biaryl phosphacycles and Pd(OAc)2 are described for Suzuki-Miyaura cross-coupling reactions of aryl bromides and chlorides. Notably, the electronically and sterically diametric biaryl phosphacycles allowed facile coupling of sterically hindered and heterocyclic substrates.
Iron Single Atom Catalyzed Quinoline Synthesis
Chen, Zhongxin,Song, Jingting,Peng, Xinwen,Xi, Shibo,Liu, Jia,Zhou, Wenhui,Li, Runlai,Ge, Rile,Liu, Cuibo,Xu, Haisen,Zhao, Xiaoxu,Li, Haohan,Zhou, Xin,Wang, Lu,Li, Xing,Zhong, Linxin,Rykov, Alexandre I.,Wang, Junhu,Koh, Ming Joo,Loh, Kian Ping
, (2021/07/21)
The production of high-value chemicals by single-atom catalysis is an attractive proposition for industry owing to its remarkable selectivity. Successful demonstrations to date are mostly based on gas-phase reactions, and reports on liquid-phase catalysis are relatively sparse owing to the insufficient activation of reactants by single-atom catalysts (SACs), as well as, their instability in solution. Here, mechanically strong, hierarchically porous carbon plates are developed for the immobilization of SACs to enhance catalytic activity and stability. The carbon-based SACs exhibit excellent activity and selectivity (≈68%) for the synthesis of substituted quinolines by a three-component oxidative cyclization, affording a wide assortment of quinolines (23 examples) from anilines and acetophenones feedstock in an efficient, atom-economical manner. Particularly, a Cavosonstat derivative can be synthesized through a one-step, Fe1-catalyzed cyclization instead of traditional Suzuki coupling. The strategy is also applicable to the deuteration of quinolines at the fourth position, which is challenging by conventional methods. The synthetic utility of the carbon-based SAC, together with its reusability and scalability, renders it promising for industrial scale catalysis.
Zinc Stabilized Azo-anion Radical in Dehydrogenative Synthesis of N-Heterocycles. An Exclusively Ligand Centered Redox Controlled Approach
Das, Siuli,Mondal, Rakesh,Chakraborty, Gargi,Guin, Amit Kumar,Das, Abhishek,Paul, Nanda D.
, p. 7498 - 7512 (2021/06/30)
Herein we report an exclusively ligand-centered redox controlled approach for the dehydrogenation of a variety of N-heterocycles using a Zn(II)-stabilized azo-anion radical complex as the catalyst. A simple, easy-to-prepare, and bench-stable Zn(II)-complex (1b) featuring the tridentate arylazo pincer, 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline, in the presence of zinc-dust, undergoes reduction to form the azo-anion radical species [1b]- which efficiently dehydrogenates various saturated N-heterocycles such as 1,2,3,4-tetrahydro-2-methylquinoline, 1,2,3,4-tetrahydro-isoquinoline, indoline, 2-phenyl-2,3-dihydro-1H-benzoimidazole, 2,3-dihydro-2-phenylquinazolin-4(1H)-one, and 1,2,3,4-tetrahydro-2-phenylquinazolines, among others, under air. The catalyst has further been found to be compatible with the cascade synthesis of these N-heterocycles via dehydrogenative coupling of alcohols with other suitable coupling partners under air. Mechanistic investigation reveals that the dehydrogenation reactions proceed via a one-electron hydrogen atom transfer (HAT) pathway where the zinc-stabilized azo-anion radical ligand abstracts the hydrogen atom from the organic substrate(s), and the whole catalytic cycle proceeds via the exclusive involvement of the ligand-centered redox events where the zinc acts only as the template.
Phenanthrenequinone-Sensitized Photocatalytic Synthesis of Polysubstituted Quinolines from 2-Vinylarylimines
Alanko, Iida,Bulatov, Evgeny,Helaja, Juho,Koivula, Juho,P?ll?nen, Topias,Talvitie, Juulia
supporting information, (2022/01/04)
Visible-light-excited 9,10-phenanthrenequinone (PQ*) was used as a photocatalyst for the synthesis of polysubstituted quinolines via the electrocyclization of 2-vinylarylimines. Up to quantitative yields of 2,4-disubstituted quinolines were received after 1 h of excitation with blue LEDs at room temperature when MgCO3 was used as an additive in DCM. On the basis of experimental and DFT studies, we propose that PQ? induces one-electron oxidation of the imine substrate that triggers the electrocyclization mechanism.