2475-92-5Relevant academic research and scientific papers
Polysubstituted Indole Synthesis via Palladium/Norbornene Cooperative Catalysis of Oxime Esters
Liu, Jiechun,Lin, Haojiang,Jiang, Huanfeng,Huang, Liangbin
supporting information, p. 484 - 489 (2022/01/20)
Polysubstituted indoles are prevalent in pharmaceuticals, agrochemicals, and organic materials. Presented herein is the fact that polyfunctionalized indoles can be efficiently constructed from easily accessible oxime esters and aryl iodides, involving a palladium/norbornene synergistic synthesis. The reaction is enabled by a unique class of electrophiles in palladium/norbornene cooperative catalysis, which are oxime esters derived from simple ketone. The broad substrate scope and high functional group tolerance could make this method attractive for the synthesis of polysubstituted indoles.
Beckmann rearrangement of ketoximes promoted by cyanuric chloride and dimethyl sulfoxide under a mild condition
Ma, Ruonan,Chen, Xueyuan,Xiao, Zhiyin,Natarajan, Mookan,Lu, Chunxin,Jiang, Xiujuan,Zhong, Wei,Liu, Xiaoming
supporting information, (2021/01/06)
Synthesis of amides via Beckmann rearrangement of ketoximes promoted by cyanuric chloride (TCT)/DMSO under mild conditions has been reported. Conditions of the Beckmann rearrangement, e.g., solvents, the ratios of TCT/DMSO, and the temperature, were investigated using diphenylmethanone oxime as a substrate. The optimized conditions were adopted to afford fourteen amides with yields ranging from 20% to 99%. A plausible mechanism involving an active dimethyl alkoxysulfonium intermediate was proposed according to the mass spectrometry analysis. To our best knowledge, this is the first case of study on Beckmann rearrangement of ketoximes promoted by TCT/DMSO under a mild condition to afford amides efficiently.
AgNO3as Nitrogen Source for Cu-Catalyzed Cyclization of Oximes with Isocyanates: A Facile Route to N-2-Aryl-1,2,3-triazoles
Liang, Jingwen,Rao, Yingqi,Zhu, Weidong,Wen, Tingting,Huang, Junjie,Chen, Zhichao,Chen, Lu,Li, Yibiao,Chen, Xiuwen,Zhu, Zhongzhi
supporting information, p. 7028 - 7032 (2021/09/14)
A versatile copper-catalyzed [3 + 1 + 1] annulation of oximes and isocyanates with AgNO3 is described. In this conversion, AgNO3 and isocyanates instead of conventional azide or diazonium reagents were used as the nitrogen source. This three-component transformation was achieved by cleaving N-O/C-H/C-N bonds and building CN/N-N bonds, which provides a strategy to prepare N-2-aryl-1,2,3-triazoles with a good substrate and functional compatibility.
Access to multi-functionalized oxazolines via silver-catalyzed heteroannulation of enamides with sulfoxonium ylides
Liu, Rui-Hua,Shan, Qi-Chao,Gao, Ya,Loh, Teck-Peng,Hu, Xu-Hong
supporting information, p. 1411 - 1414 (2020/10/29)
Disclosed herein is an efficient Ag-catalyzed [4 + 1] heteroannulation reaction of enamides with α-carbonyl sulfoxonium ylides. The diastereoselective transformation provides a practical access to a diverse range of multi-functionalized oxazoline derivatives. The synthetic utility of the resultant tetra-substituted oxazolines is further demonstrated by a series of useful manipulations into valuable building blocks of pharmaceutical relevance.
Rhodium(III)-Catalyzed Direct C-H Arylation of Various Acyclic Enamides with Arylsilanes
Li, Xiaolan,Sun, Kai,Shen, Wenjuan,Zhang, Yong,Lu, Ming-Zhu,Luo, Xuzhong,Luo, Haiqing
supporting information, p. 31 - 36 (2021/01/09)
The stereoselective β-C(sp2)-H arylation of various acyclic enamides with arylsilanes via Rh(III)-catalyzed cross-coupling reaction was illustrated. The methodology was characterized by extraordinary efficacy and stereoselectivity, a wide scope of substrates, good functional group tolerance, and the adoption of environmentally friendly arylsilanes. The utility of this present method was evidenced by the gram-scale synthesis and further elaboration of the product. In addition, Rh(III)-catalyzed C-H activation is considered to be the critical step in the reaction mechanism.
Visible-light-promoted olefinic trifluoromethylation of enamides with CF3SO2Na
Chen, Kai,Chen, Yixuan,Guan, Jianping,Tang, Kai,Wang, Zhujun,Xiang, Haoyue,Yang, Hua
supporting information, p. 7475 - 7479 (2021/09/08)
A visible-light-promoted olefinic C-H trifluoromethylation of enamides was developed by employing cheap and stable Langlois’ reagent as the CF3source. A series of β-CF3enamides were obtained in moderate to good yields with highE-isomer selectivity under mild conditions. Preliminary mechanistic studies suggest that molecular oxygen acts as the terminal oxidant for this net oxidative process, and theEisomer selectivity could be well explained by a base-assisted deprotonation of the cation intermediate.
Rhodium-Catalyzed C?H Activation/Annulation Cascade of Aryl Oximes and Propargyl Alcohols to Isoquinoline N-Oxides
Li, Yuan,Fang, Feifei,Zhou, Jianhui,Li, Jiyuan,Wang, Run,Liu, Hong,Zhou, Yu
supporting information, p. 3305 - 3310 (2021/05/17)
A β-hydroxy elimination instead of common oxidization to carbonyl group in secondary propargyl alcohols was successfully developed to form 2-benzyl substituted isoquinoline N-oxides by a Rhodium-catalyzed C?H activation and annulation cascade, in which moderate to excellent yields (up to 92%) could be obtained under mild reaction conditions, along with good regioselectivity, broad generality and applicability. (Figure presented.).
Synthesis of 5-Vinyl-2-isoxazolines by Palladium-Catalyzed Intramolecular O-Allylation of Ketoximes
Fernandes, Rodney A.,Gangani, Ashvin J.,Panja, Arpita
supporting information, p. 6227 - 6231 (2021/08/18)
An efficient method for the synthesis of 5-vinyl-2-isoxazolines by Pd-catalyzed intramolecular O-allylation of ketoximes has been developed. The reaction involves Pd(0)-catalyzed π-allyl formation via leaving group ionization or Pd(II)-catalyzed allylic C-H activation followed by intramolecular nucleophilic oxime oxygen attack. This methodology has been elaborated to various value-added products by epoxidation, Wacker oxidation, cross-metathesis, hydroboration-oxidation, dihydroxylation, and catalytic hydrogenation.
Rhodium(iii)-catalyzed asymmetric [4+1] spiroannulations of: O -pivaloyl oximes with α-diazo compounds
Chang, Junbiao,Deng, Wei-Qiao,Kong, Lingheng,Li, Xingwei,Liu, Bingxian,Sun, Lincong,Wang, Fen,Zhao, Yanlian
supporting information, p. 8268 - 8271 (2021/08/25)
Chiral RhIII catalysts can catalyze the asymmetric [4+1] spiroannulation of O-pivaloyl oximes with α-diazo homophthalimides under redox-neutral and acid/base-neutral conditions, leading to formation of chiral spirocyclic imines as a result of C-H activation and N-O cleavage. The reaction proceeded with high efficiency and features broad substrate scope, mild reaction conditions, and high to excellent enantioselectivities. This journal is
Asymmetric Full Saturation of Vinylarenes with Cooperative Homogeneous and Heterogeneous Rhodium Catalysis
Andersson, Pher G.,Massaro, Luca,Peters, Bram B. C.,Wu, Haibo,Yang, Jianping,Zheng, Jia
supporting information, p. 20377 - 20383 (2021/12/03)
Homogeneous and heterogeneous catalyzed reactions can seldom operate synergistically under the same conditions. Here we communicate the use of a single rhodium precursor that acts in both the homogeneous and heterogeneous phases for the asymmetric full saturation of vinylarenes that, to date, constitute an unmet bottleneck in the field. A simple asymmetric hydrogenation of a styrenic olefin, enabled by a ligand accelerated effect, accounted for the facial selectivity in the consecutive arene hydrogenation. Tuning the ratio between the phosphine ligand and the rhodium precursor controlled the formation of homogeneous and heterogeneous catalytic species that operate without interference from each other. The system is flexible in terms of both the chiral ligand and the nature of the external olefin. We anticipate that our findings will promote the development of asymmetric arene hydrogenations.
