2918-69-6Relevant academic research and scientific papers
Bromo Radical-Mediated Photoredox Aldehyde Decarbonylation towards Transition-Metal-Free Hydroalkylation of Acrylamides at Room Temperature
Sun, Zhaozhao,Huang, Huawen,Wang, Qiaolin,Deng, Guo-Jun
supporting information, p. 453 - 458 (2021/12/03)
Herein, we report a visible-light-mediated hydroalkylation reaction of alkenes using easily available aldehydes as alkyl sources via bromo radical-promoted photoredox decarbonylation. This protocol provides an alternative entry to C(sp3)?C(sp3) bond formation and features considerable advantages including mild and clean reaction conditions, obviation for transition-metal catalyst, and good functional group compatibility.
A benzene-bridged divanadium complex-early transition metal catalyst for alkene alkylarylation with PhI(O2CR)2viadecarboxylation
Zhang, Lei,Zhou, Hongfei,Bai, Shaokun,Li, Shaodan
supporting information, p. 3201 - 3206 (2021/03/16)
The synthesis, structure and catalytic activity of a benzene-bridged divanadium complex were comprehensively studied. The reduction of (Nacnac)VCl2(1) (Nacnac = (2,6-iPr2C6H3NCMe)2HC) supported by β-diketiminate with potassium graphite (KC8) by employing benzene as the solvent allows access to the benzene-bridged inverted-sandwich divanadium complex (μ-η6:η6-C6H6)[V(Nacnac)]2(2a), which can catalyze alkene alkylarylation with hypervalent iodine(iii) reagents (HIRs)viadecarboxylation to generate regioselectively diverse indolinones. Furthermore, the mild nature of this reaction was amenable to a wide range of functionalities on alkenes and HIRs. Mechanistic studies revealed a relay sequence of decarboxylative radical alkylation/radical arylation/oxidative re-aromatization.
Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
Das, Sanju,De Sarkar, Suman,Mandal, Tanumoy
supporting information, (2021/12/10)
A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
Copper-Catalyzed Radical N-Demethylation of Amides Using N-Fluorobenzenesulfonimide as an Oxidant
Yi, Xuewen,Yi, Xuewen,Lei, Siyu,Liu, Wangsheng,Che, Fengrui,Yu, Chunzheng,Liu, Xuesong,Wang, Zonghua,Zhou, Xin,Zhang, Yuexia
, p. 4583 - 4587 (2020/05/05)
An unprecedented N-demethylation of N-methyl amides has been developed by use of N-fluorobenzenesulfonimide as an oxidant with the aid of a copper catalyst. The conversion of amides to carbinolamines involves successive single-electron transfer, hydrogen-atom transfer, and hydrolysis, and is accompanied by formation of N-(phenylsulfonyl)benzenesulfonamide. Carbinolamines spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.
Catalyst-free and selective trifluoromethylative cyclization of acryloanilides using PhICF3Cl
Guo, Jia,Xu, Cong,Wang, Ling,Huang, Wanqiao,Wang, Mang
supporting information, p. 4593 - 4599 (2019/05/17)
Trifluoromethylation-triggered cyclization of alkenes provides a useful route to CF3-containing cyclic compounds. Current approaches to generate CF3-based initiators from a CF3 source require a catalyst or an activator. This work describes a catalyst-free protocol to innately produce electrophilic CF3 species from PhICF3Cl for trifluoromethylative cyclization of acryloanilides. A new domino biscyclization of dienes has been developed leading to trifluoroethylated tetrahydroindenoquinolinones with chemo- and stereo-selectivity.
Silver-Catalyzed Decarboxylative Radical Addition/Cyclization of α,α-Difluoroarylacetic Acids with Acrylamides To Synthesize Difluorinated Oxindoles
Li, Yin-Long,Wang, Ji-Bo,Wang, Xue-Lin,Cao, Yang,Deng, Jun
supporting information, p. 6052 - 6059 (2017/11/14)
A facile silver-catalyzed decarboxylative radical addition/cyclization reaction of α,α-difluoroarylacetic acids and acrylamides has been disclosed. The method provides a highly attractive approach to synthesize a series of difluorinated oxindoles that contain various functional groups in moderate to good yields under mild conditions. Moreover, experimental studies reveal that the CF2 group of the α,α-difluoroarylacetic acids plays a vital role in the transformation.
UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
supporting information, p. 1034 - 1037 (2015/03/30)
UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
The carbomethylation of arylacrylamides leading to 3-ethyl-3-substituted indolin-2-one by cascade radical addition/cyclization
Dai, Qiang,Yu, Jintao,Jiang, Yan,Guo, Songjin,Yang, Haitao,Cheng, Jiang
supporting information, p. 3865 - 3867 (2014/04/03)
An FeCl2-promoted carbomethylation of arylacrylamides by di-tert-butyl peroxide (DTBP) is achieved, leading to 3-ethyl-3-substituted indolin-2-one in high yield. The reaction tolerates a series of functional groups, such as cyano, nitro, ethyloxy carbonyl, bromo, chloro, and trifluoromethyl groups. The radical methylation and arylation of the alkenyl group are involved in this reaction. This journal is the Partner Organisations 2014.
Synthesis of oxindoles through silver-catalyzed trifluoromethylation-, difluoromethylation- and arylsulfonylation-cyclization reaction of N-arylacrylamides
Liu, Jidan,Zhuang, Shaobo,Gui, Qingwen,Chen, Xiang,Yang, Zhiyong,Tan, Ze
supporting information, p. 3196 - 3202 (2014/06/09)
Efficient synthesis of trifluoromethyl and difluoromethyl-substituted oxindoles was achieved by reacting Langlois reagent or Baran reagent with N-arylacrylamides. However, the reaction of aryl sulfinic acid sodium salts with N-arylacrylamides did not give the desulfinative products, instead, aryl sulfonated products were produced. Copyright
Catalyst-free direct arylsulfonylation of N-arylacrylamides with sulfinic acids: A convenient and efficient route to sulfonated oxindoles
Wei, Wei,Wen, Jiangwei,Yang, Daoshan,Du, Juan,You, Jinmao,Wang, Hua
supporting information, p. 2988 - 2991 (2014/06/10)
A simple, efficient and catalyst-free procedure has been developed for the construction of sulfonated oxindoles via the direct arylsulfonylation of N-arylacrylamides with sulfinic acids. The present protocol, which simply utilizes cheap oxidants, readily-available starting materials, and catalyst-free conditions, provides an alternative and highly attractive approach to a series of sulfonated oxindoles with high atom efficiency and excellent functional group tolerance. This journal is the Partner Organisations 2014.
