22002-44-4Relevant academic research and scientific papers
Electro-Oxidative Selective Esterification of Methylarenes and Benzaldehydes
Yu, Congjun,?zkaya, Bünyamin,Patureau, Frederic W.
supporting information, p. 3682 - 3687 (2021/02/01)
A mild and green electro-oxidative protocol to construct aromatic esters from methylarenes and alcohols is herein reported. Importantly, the reaction is free of metals, chemical oxidants, bases, acids, and operates at room temperature. Moreover, the design of the electrolyte was found critical for the oxidation state and structure of the coupling products, a rarely documented effect. This electro-oxidative coupling process also displays exceptional tolerance of many fragile easily oxidized functional groups such as hydroxy, aldehyde, olefin, alkyne, as well as neighboring benzylic positions. The enantiomeric enrichment of some chiral alcohols is moreover preserved during this electro-oxidative coupling reaction, making it overall a promising synthetic tool.
In situ Generation of Hypervalent Iodine Reagents for the Electrophilic Chlorination of Arenes
Granados, Albert,Jia, Zhiyu,del Olmo, Marc,Vallribera, Adelina
, p. 2812 - 2818 (2019/04/08)
Efficient metal-free methods for the electrophilic chlorination of arenes using PIFA and simple chlorine sources are reported. The in situ formation of PhI(Cl)OCOCF3 from PIFA and KCl is proposed, which resulted in a chlorinating species for moderately activated arenes. Moreover, the in situ formation of PhICl2 from PIFA and TMSCl resulted in an excellent approach for the chlorination of a great variety of arenes (20 examples) in high yields, even when working on a multigram scale.
Visible Light-Induced Oxidative Chlorination of Alkyl sp3 C-H Bonds with NaCl/Oxone at Room Temperature
Zhao, Mengdi,Lu, Wenjun
supporting information, p. 4560 - 4563 (2017/09/11)
A visible light-induced monochlorination of cyclohexane with sodium chloride (5:1) has been successfully accomplished to afford chlorocyclohexane in excellent yield by using Oxone as the oxidant in H2O/CF3CH2OH at room temperature. Other secondary and primary alkyl sp3 C-H bonds of cycloalkanes and functional branch/linear alkanes can also be chlorinated, respectively, under similar conditions. The selection of a suitable organic solvent is crucial in these efficient radical chlorinations of alkanes in two-phase solutions. It is studied further by the achievement of high chemoselectivity in the chlorination of the benzyl sp3 C-H bond or the aryl sp2 C-H bond of toluene.
An efficient monochlorination of electron-rich aromatic compounds catalysed by ammonium iodide
Min, Zhu,Ying-Guo, Fang
, p. 197 - 199 (2014/05/06)
An efficient monochlorination of electron-rich aromatic compounds is developed, with which a series of regioselective monochlorinated products are obtained in good yields. In the reaction, ammonium iodide is used as catalyst and m-chloroperbenzoic acid is used as the terminal oxidant. Ammonium iodide is first oxidised to hypoiodous acid by m-chloroperbenzoic acid. The in situ generated active iodine species then reacts with the aromatic compound to form the active hypervalent iodine intermediate in two steps and this reacts with lithium chloride to afford eventually the chlorinated compounds.
Synthesis of deuterated benzopyran derivatives as selective COX-2 inhibitors with improved pharmacokinetic properties
Zhang, Yanmei,Tortorella, Micky D.,Wang, Yican,Liu, Jianqi,Tu, Zhengchao,Liu, Xiaorong,Bai, Yang,Wen, Dingsheng,Lu, Xin,Lu, Yongzhi,Talley, John J.
, p. 1162 - 1166 (2014/12/10)
We designed a series of specifically deuterated benzopyran analogues as new COX-2 inhibitors with the aim of improving their pharmacokinetic properties. As expected, the deuterated compounds retained potency and selectivity for COX-2. The new molecules possess improved pharmacokinetic profiles in rats compared to their nondeuterated congeners. Most importantly, the new compounds showed pharmacodynamic efficacy in several murine models of inflammation and pain. The benzopyran derivatives were separated into their enantiomers, and the activity was found to reside with the S-isomers. To streamline the synthesis of the desired S-isomers, an organocatalytic asymmetric domino oxa-Michael/aldol condensation reaction was developed for their preparation.
The oxidative halogenations of arenes in water using hydrogen peroxide and halide salts over an ionic catalyst containing sulfo group and hexafluorotitanate
Wang, Ling,Wang, Sa-Sa,Vo-Thanh, Giang,Liu, Ye
, p. 56 - 62 (2013/05/09)
An ionic compound, bis[1-methyl-3-(3′-sulfopropyl)imidazolium] hexafluorotitanate (1), was proved to be the efficient and recyclable catalyst for the oxidative halogenations of arenes in water using H2O 2 as the oxidant and halide salts as the halogenation sources. The mono-halogenated products were obtained selectively by this method. The synergetic catalytic effect coming from the two incorporated functionalities of SO3H and [TiF6]2- was manifested in 1. The halogenation rate catalyzed by 1 was in the ranking of NaBr NaCl > KI. The UV-vis and FT-IR analyses indicated that the successful formation and regeneration of the active peroxo-Ti species (1A) with the aid of proton acid guaranteed the recycling uses of 1.
An efficient chlorination of aromatic compounds using a catalytic amount of iodobenzene
Li, Ting-Ting,Xu, Cui,Xiang, Chang-Bin,Yan, Jie
, p. 535 - 538 (2013/07/27)
An efficient method was developed for chlorination of aromatic compounds with electron-donating groups using iodobenzene as the catalyst and m-chloroperbenzoic acid as the terminal oxidant in the presence of 4-methylbenzenesulfonic acid in THF at room temperature for 24 h, and a series of the monochlorinated compounds was obtained in good yields. In this protocol, the catalyst iodobenzene was first oxidized into the hypervalent iodine intermediate, which then treated with lithium chloride and finally reacted with aromatic compounds to form the chlorinated compounds.
Bis- N -heterocyclic carbene palladium(IV) tetrachloride complexes: Synthesis, reactivity, and mechanisms of direct chlorinations and oxidations of organic substrates
McCall, A. Scott,Wang, Hongwang,Desper, John M.,Kraft, Stefan
supporting information; experimental part, p. 1832 - 1848 (2011/04/15)
This Article describes the preparation and isolation of novel octahedral CH2-bridged bis-(N-heterocyclic carbene)palladium(IV) tetrachlorides of the general formula LPdIVCl4 [L = (NHC)CH 2(NHC)] from LPdIICl2 and Cl2. In intermolecular, nonchelation-controlled transformations LPdIVCl 4 reacted with alkenes and alkynes to 1,2-dichlorination adducts. Aromatic, benzylic, and aliphatic C-H bonds were converted into C-Cl bonds. Detailed mechanistic investigations in the dichlorinations of alkenes were conducted on the 18VE PdIV complex. Positive solvent effects as well as kinetic measurements probing the impact of cyclohexene and chloride concentrations on the rate of alkene chlorination support a PdIV-Cl ionization in the first step. Product stereochemistry and product distributions from various alkenes also support Cl+-transfer from the pentacoordinated PdIV-intermediate LPdIVCl 3+ to olefins. 1-Hexene/3-hexene competition experiments rule out both the formation of π-complexes along the reaction coordinate as well as in situ generated Cl2 from a reductive elimination process. Instead, a ligand-mediated direct Cl+-transfer from LPd IVCl3+ to the π-system is likely to occur. Similarly, C-H bond chlorinations proceed via an electrophilic process with in situ formed LPdIVCl3+. The presence of a large excess of added Cl- slows cyclohexene chlorination while the presence of stoichiometric amounts of chloride accelerates both PdIV-Cl ionization and Cl+-transfer from LPdIVCl3 +. 1H NMR titrations, T1 relaxation time measurements, binding isotherms, and Job plot analysis point to the formation of a trifurcated Cl-...H-C bond in the NHC-ligand periphery as a supramolecular cause for the accelerated chemical events involving the metal center.
Palladium-catalyzed cross-coupling alkylation of arenediazonium o-benzenedisulfonimides
Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
, p. 474 - 478 (2008/09/21)
Arenediazonium o-benzenedisulfonimides were reacted with tetramethyltin, tetrabutyltin or trialkylboranes. The reactions, carried out in the presence of palladium(II) derivatives as precatalysts, gave the methylation and alkylation products with good over
A simple, efficient and regioselective oxychlorination of aromatic compounds using ammonium chloride and oxone
Narender,Mohan, K.V.V. Krishna,Srinivasu,Kulkarni,Raghavan
, p. 1335 - 1338 (2007/10/03)
A simple, efficient, mild and regioselective method for oxychlorination of aromatic compounds is reported. The electrophilic substitution of chlorine generated in situ from NH4Cl as a chlorine source and oxone as an oxidant is reported for the first time.
