2436-93-3Relevant academic research and scientific papers
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.
RhIII-Catalyzed Direct Heteroarylation of C(sp3)-H and C(sp2)-H Bonds in Heterocycles with N-Heteroaromatic Boronates
Wang, Huai-Wei,Wu, Jia-Xue,Qiao, Yu-Han,Li, Yong-Fei,Li, Da-Cheng,Dou, Jian-Min,Yao, Qing-Xia,Lu, Yi
supporting information, p. 7177 - 7182 (2021/09/18)
Herein, we disclose a RhIII-catalyzed heteroarylation of C(sp3)-H and C(sp2)-H bonds in heterocycles with organoboron reagents. This protocol displays high efficiency and excellent functional group tolerance. A range of heterocyclic boronates with strong coordinating atoms, including pyridine, pyrimidine, pyrazole, thiophene, and furan derivatives, can be extensively served as the coupling reagents. The direct heteroarylation method could supply potential application in terms of the synthesis of drug molecules with multiple heterocycles.
Cobalt-catalyzed ring-opening addition of azabenzonorbornadienes: Via C(sp3)-H bond activation of 8-methylquinoline
Tan, Heng,Khan, Ruhima,Xu, Dandan,Zhou, Yongyun,Zhang, Xuexin,Shi, Guangrui,Fan, Baomin
supporting information, p. 12570 - 12573 (2020/11/02)
The first ring-opening addition of a benzylic C(sp3)-H bond to azabenzonorbornadienes is demonstrated. The reaction proceeded under the catalytic system of [Cp?CoI2(CO)], AgSbF6 and Fe(OAc)2 in PhOMe. The methodology showed a good substrate scope with up to 96 yield. The relative configuration of the product was determined as cis-configuration by X-ray crystallography.
Iodonium Ylides as Carbene Precursors in Rh(III)-Catalyzed C-H Activation
Jiang, Yuqin,Li, Pengfei,Li, Xingwei,Liu, Bingxian,Zhao, Jie
supporting information, p. 7475 - 7479 (2020/10/12)
The rhodium(III)-catalyzed coupling of C-H substrates with iodonium ylides has been realized for the efficient synthesis of diverse cyclic skeletons, where the iodonium ylides have been identified as efficient and outstanding carbene precursors. The reaction systems are applicable to both sp2 and sp3 C-H substrates under mild and redox-neutral conditions. The catalyst loading can be as low as 0.5 mol % in a gram-scale reaction. Representative products exhibit cytotoxicity toward human cancer cells at nanomolar levels.
Rh(iii)-Catalyzed straightforward arylation of 8-methyl/formylquinolines using diazo compounds
Ghosh, Bidhan,Samanta, Rajarshi
supporting information, p. 6886 - 6889 (2019/06/18)
A straightforward Rh(iii)-catalyzed general strategy was developed for the introduction of naphthol/phenol moieties to the C(sp3)-H bond of 8-methylquinoline using diazonaphthalen-2(1H)-ones/quinone diazides. The developed method was further extended towards the arylation of 8-formylquinolines to accomplish diarylketone derivatives. The method is simple, relatively rapid, and chemo and regioselective with a wide scope and functional group tolerance. The synthetic utility was established through gram-scale synthesis and biologically active molecule construction.
Palladium-Catalyzed C-H Bond Functionalization Reactions Using Phosphate/Sulfonate Hypervalent Iodine Reagents
He, Yimiao,Huang, Lilan,Xie, Limei,Liu, Peng,Wei, Qiongmei,Mao, Fangfang,Zhang, Xuehong,Huang, Jun,Chen, Sijing,Huang, Chusheng
, p. 10088 - 10101 (2019/08/22)
A new and operationally simple approach for palladium-catalyzed C-H functionalization reactions utilizing an organophosphorus/sulfonate hypervalent iodine reagent as both an oxidant and the source of a functional group has been developed. Through this method, the oxidative phosphorylation-, sulfonation-, and hydroxylation of unactivated benzyl C(sp3)-H bonds, along with the hydroxylation and arylation of aryl C(sp2)-H bonds, are successfully realized under mild conditions and with excellent site-selectivity. The versatile C-OSO2R bond provides a platform for a wide array of subsequent diversification reactions.
Rh-Catalyzed Direct Amination of Unactivated C(sp3)?H bond with Anthranils Under Mild Conditions
Tang, Conghui,Zou, Miancheng,Liu, Jianzhong,Wen, Xiaojin,Sun, Xiang,Zhang, Yiqun,Jiao, Ning
supporting information, p. 11165 - 11169 (2016/08/03)
C?N Bond formation is of great significance due to the ubiquity of nitrogen-containing compounds. Here, a mild and efficient RhIII-catalyzed C(sp3)?H aryl amination reaction is reported. Anthranil is employed as the nitrogen source with 100 % atom efficiency. This C?H amination reaction exhibits broad substrate scope without using any external oxidants. Mechanistic studies including rhodacycle intermediates, H–D exchange, kinetic isotope effect (KIE) experiments, and in situ IR are presented.
Highly Enantioselective Direct Synthesis of Endocyclic Vicinal Diamines through Chiral Ru(diamine)-Catalyzed Hydrogenation of 2,2′-Bisquinoline Derivatives
Ma, Wenpeng,Zhang, Jianwei,Xu, Cong,Chen, Fei,He, Yan-Mei,Fan, Qing-Hua
supporting information, p. 12891 - 12894 (2016/10/04)
An asymmetric hydrogenation of 2,2′-bisquinoline and bisquinoxaline derivatives, catalyzed by chiral cationic ruthenium diamine complexes, was developed. A broad range of chiral endocyclic vicinal diamines were obtained in high yields with excellent diastereo- and enantioselectivity (up to 93:7 dl/meso and >99 % ee). These chiral diamines could be easily transformed into a new class of chiral N-heterocyclic carbenes (NHCs), which are important but difficult to access.
Rhodium(III)-catalyzed intermolecular amidation with azides via C(sp 3)-H functionalization
Wang, Nuancheng,Li, Renhe,Li, Liubo,Xu, Shansheng,Song, Haibin,Wang, Baiquan
, p. 5379 - 5385 (2014/06/23)
The amidation reactions of 8-methylquinolines with azides catalyzed by a cationic rhodium(III) complex proceed efficiently to give quinolin-8- ylmethanamine derivatives in good yields via C(sp3)-H bond activation under external oxidant-free conditions. A catalytically competent five-membered rhodacycle has been isolated and characterized, revealing a key intermediate in the catalytic cycle.
N-Mesityl-C-acylketenimines: 1,5-Sigmatropic Shifts and Electrocyclization to Quinolines
Rao, V. V. Ramana,Fulloon, Belinda E.,Bernhardt, Paul V.,Koch, Rainer,Wentrup, Curt
, p. 5779 - 5786 (2007/10/03)
Flash vacuum thermolysis (FVT) of triazoles 6a- c generates α-oxoketenimines 10, the ester 10a being isolable. FVT of pyrroledione 8 generates the isomeric imidoylketene 9a. Ketenes 9 and ketenimines 10 undergo thermal interconversion by 1,3-shifts of methoxy and dimethylamino groups under mild FVT conditions (ca. 350-400°C). Both 9 and 10 are directly observable by IR spectroscopy at either 77 K or on Ar matrix isolation at 12 K. On FVT at temperatures above ca. 400°C, the ketenimines 10 undergo a 1,5-H shift to o-quinoid imines 12/13, followed by electrocyclization to dihydroquinolines 14 (unobserved) and 15 (observed by NMR). The latter are easily oxidized to alkylquinoline-3-carboxylates or quinoline-3-carboxamides 16 by atmospheric oxygen. Ab initio calculations on model compounds 18-23 predict an energy barrier of ca. 38 kcal mol-1 (161 kJ mol-1) for the 1,5-H shift in N-(o-methylphenyl)ketenimines via the transition state TS19 followed by an electrocyclization barrier to dihydroquinoline 23a via TS22a of ca. 16 kcal mol-1.
