5969-83-5Relevant articles and documents
Cp*Rh(iii)/boron hybrid catalysis for directed C-H addition to β-substituted α,β-unsaturated carboxylic acids
Hirata, Yuki,Kojima, Masahiro,Matsunaga, Shigeki,Tanaka, Ryo,Yoshino, Tatsuhiko
supporting information, p. 76 - 79 (2021/12/29)
The C-H bond addition reaction of 2-phenylpyridine derivatives with α,β-unsaturated carboxylic acids catalyzed by Cp*Rh(iii)/BH3·SMe2is reported. Activation of C-H bonds with the rhodium catalyst and activation of α,β-unsaturated carboxylic acids with the boron catalyst cooperatively work, and a BINOL-urea hybrid ligand significantly improved the reactivity. With the optimized hybrid catalytic system, various β-disubstituted carboxylic acids were obtained under mild reaction conditions.
Nickel-Catalyzed Reductive 2-Pyridination of Aryl Iodides with Difluoromethyl 2-Pyridyl Sulfone
Miao, Wenjun,Ni, Chuanfa,Xiao, Pan,Jia, Rulong,Zhang, Wei,Hu, Jinbo
supporting information, p. 711 - 715 (2021/01/26)
A novel nickel-catalyzed reductive cross-coupling between aryl iodides and difluoromethyl 2-pyridyl sulfone (2-PySO2CF2H) enables C(sp2)-C(sp2) bond formation through selective C(sp2)-S bond cleavage, which demonstrates the new reactivity of 2-PySO2CF2H reagent. This method employs readily available nickel catalyst and sulfones as cross-electrophile coupling partners, providing facile access to biaryls under mild reaction conditions without pregeneration of arylmetal reagents.
Pd-Catalysed Suzuki-Miyaura cross-coupling of aryl chlorides at low catalyst loadings in water for the synthesis of industrially important fungicides
Goetz, Roland,Hashmi, A. Stephen K.,Orecchia, Patrizio,Petkova, Desislava Slavcheva,Rominger, Frank,Schaub, Thomas
supporting information, p. 8169 - 8180 (2021/11/01)
The Suzuki-Miyaura coupling reaction of electron-poor aryl chlorides in the synthesis of crop protection-relevant active ingredients in water is disclosed. Optimisation of the reaction conditions allowed running the reaction with 50 ppm of Pd-catalyst loading without an additional organic solvent in the cross-coupling reaction step in short reaction times. The system was optimised for the initial cross-coupling step of the large scale produced fungicides Boscalid, Fluxapyroxad and Bixafen up to 97% yield. It is also shown that the Suzuki-Miyaura reaction can be easily scaled up to 50 g using a simple product separation and purification using environmentally benign solvents in the work-up. To show the usability of this method, it was additionally applied in the three-step synthesis of the desired active ingredients.
Access to Branched Allylarenes via Rhodium(III)-Catalyzed C-H Allylation of (Hetero)arenes with 2-Methylidenetrimethylene Carbonate
Zhang, Shang-Shi,Zheng, Yi-Chuan,Zhang, Zi-Wu,Chen, Shao-Yong,Xie, Hui,Shu, Bing,Song, Jia-Lin,Liu, Yan-Zhi,Zeng, Yao-Fu,Zhang, Luyong
supporting information, p. 5719 - 5723 (2021/08/16)
A rhodium(III)-catalyzed C-H allylation of (hetero)arenes by using 2-methylidenetrimethylene carbonate as an efficient allylic source has been developed for the first time. Five different directing groups including oxime, N-nitroso, purine, pyridine, and pyrimidine were compatible, delivering various branched allylarenes bearing an allylic hydroxyl group in moderate to excellent yields.
Three-Component Couplings among Heteroarenes, Difluorocyclopropenes, and Water via C-H Activation
Liu, Xuexin,Chen, Jian,Yang, Chunyan,Wu, Zhouping,Li, Zhiyang,Shi, Yuesen,Huang, Tianle,Yang, Zhongzhen,Wu, Yong
supporting information, p. 6831 - 6835 (2021/09/08)
Three-component couplings have been realized for efficiently constructing various nitrogen-containing skeletons via C-H activation, where difluorocyclopropenes have been first identified as coupling partners. Many substrates including sp2 and sp3 C-H substrates were well tolerated, furnishing the corresponding products in good yields. Furthermore, a catalyst-dependent reaction was also developed, enabling divergent construction of two different frameworks. The application value of these reactions was demonstrated in gram-scale experiments with as little as 1 mol % catalyst.
Rhodium-Catalyzed Additive-Free C?H Ethoxycarbonylation of (Hetero)Arenes with Diethyl Dicarbonate as a CO Surrogate
Kawai, Yuya,Liao, Yumeng,Matsuda, Takanori,Suzuki, Hirotsugu
supporting information, p. 4938 - 4942 (2021/09/30)
A rhodium-catalyzed C(sp2)-H ethoxycarbonylation of indoles and arylpyridines using diethyl dicarbonate was developed. The catalytic process features an additive-free ethoxycarbonylation reaction, in which only ethanol and CO2 are produced as byproducts, providing a CO-free and operationally simple protocol. The introduced ethoxycarbonyl group is easily transformed into other ester and amide functionalities in a single step. Moreover, the reaction can be successfully applied on gram scale, and allows for the efficient synthesis of indole-2-carboxylic acid esters and isophthalates.
Meta-dehydrogenative alkylation of arenes with ethers, ketones, and esters catalyzed by ruthenium
Li, Gang,Gao, Yuan,Jia, Chunqi,Wang, Shichong,Yan, Bingxu,Fang, Yu,Yang, Suling
supporting information, p. 8758 - 8763 (2020/12/02)
A meta-dehydrogenative alkylation of arenes with cyclic ethers, ketones, and esters catalyzed by ruthenium is achieved in the presence of a di-tert-butyl peroxide (DTBP) oxidant. Interestingly, when quinoline and isoquinoline are employed as the directing group, or a chain ether as alkylation reagent, the system produces Minisci reaction products. Mechanistic study indicates that meta-dehydrogenative alkylation is a radical process initiated by DTBP with the assistance of a CAr-Ru bond ortho/para-directing effect.
A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles
Bai, Rongxian,Gu, Yanlong,Lai, Bingbing,Li, Minghao,Liu, Ping,Ye, Meng
supporting information, p. 2888 - 2902 (2020/12/22)
A waste biomass, sodium lignosulfonate, was treated with sodium 2-formylbenzenesulfonate, and the phenylaldehyde condensation product was then used as a robust supporting material to immobilize a copper species. The so-obtained catalyst was characterized by many physicochemical methods including FTIR, EA, FSEM, FTEM, XPS, and TG. This catalyst exhibited excellent catalytic activity in the synthesis of nitrogen-containing heterocycles such as tricyclic indoles bearing 3,4-fused seven-membered rings, 2-arylpyridines, aminonaphthalenes and 3-phenylisoquinolines. In addition, this catalyst showed to be recyclable and could be reused several times without significant loss in activity during the course of the reaction process.
Photoarylation of Pyridines Using Aryldiazonium Salts and Visible Light: An EDA Approach
Bartolomeu, Aloisio De A.,Brocksom, Timothy J.,De Oliveira, Kleber T.,No?l, Timothy,Silva, Rodrigo C.
, (2019/08/26)
A metal-free methodology for the photoarylation of pyridines, in water, is described giving 2 and 4-arylated-pyridines in yields up to 96percent. The scope of the aryldiazonium salts is presented showing important results depending on the nature and position of the substituent group in the diazonium salt, that is, electron-donating or electron-withdrawing in the ortho, meta, or para positions. Further heteroaromatics were also successfully photoarylated. Mechanistic studies and comparison between our methodology and similar metal-catalyzed procedures are presented, suggesting the occurrence of a visible-light EDA complex which generates the aryl radical with no need for an additional photocatalyst.
Reversible Concerted Metalation-Deprotonation C-H Bond Activation by [Cp*RhCl2]2
Vanderweide, Andrew I.,Brennessel, William W.,Jones, William D.
supporting information, p. 12960 - 12965 (2019/10/11)
The reversibility of the concerted metalation-deprotonation exchange of eight para-substituted phenylpyridines is examined with the parent Cp*RhCl(κ-C,N-NC5H4-C6H4). Equilibrium constants are determined, and the free energies are used to extract the most important parameters that control the thermodynamics. Keq values are found to correlate best with heterolytic C-H bond strengths but in a way that is not obvious considering the electrophilic nature of these activations.
