117763-47-0Relevant academic research and scientific papers
Diradicals Photogeneration from Chloroaryl-Substituted Carboxylic Acids
Di Terlizzi, Lorenzo,Protti, Stefano,Ravelli, Davide,Fagnoni, Maurizio
supporting information, (2022/04/09)
With the aim of generating new, thermally inaccessible diradicals, potentially able to induce a double-strand DNA cleavage, the photochemistry of a set of chloroaryl-substituted carboxylic acids in polar media was investigated. The photoheterolytic cleavage of the Ar?Cl bond occurred in each case to form the corresponding triplet phenyl cations. Under basic conditions, the photorelease of the chloride anion was accompanied by an intramolecular electron-transfer from the carboxylate group to the aromatic radical cationic site to give a diradical species. This latter intermediate could then undergo CO2 loss in a structure-dependent fashion, according to the stability of the resulting diradical, or abstract a hydrogen atom from the medium. In aqueous environment at physiological pH (pH=7.3), both a phenyl cation and a diradical chemistry was observed. The mechanistic scenario and the role of the various intermediates (aryl cations and diradicals) involved in the process was supported by computational analysis.
C?Boron Enolates Enable Palladium Catalyzed Carboboration of Internal 1,3-Enynes
Chrostowska, Anna,Lamine, Walid,Li, Bo,Liu, Shih-Yuan,Miqueu, Karinne,Sotiropoulos, Jean-Marc,Wang, Ziyong,Wu, Jason
supporting information, p. 21231 - 21236 (2021/09/02)
A new family of carbon-bound boron enolates, generated by a kinetically controlled halogen exchange between chlorocatecholborane and silylketene acetals, is described. These C?boron enolates are demonstrated to activate 1,3-enyne substrates in the presence of a Pd0/Senphos ligand complex, resulting in the first examples of a carboboration reaction of an alkyne with enolate-equivalent nucleophiles. Highly substituted dienyl boron building blocks are produced in excellent site-, regio-, and diastereoselectivity by the described catalytic cis-carboboration reaction.
Sm/HOAc/EtOH system-mediated reduction of Baylis-Hillman acetates
Liu, Yunkui,Mao, Dajie,Xu, Danqian,Xu, Zhenyuan,Zhang, Yongmin
, p. 4389 - 4397 (2008/03/14)
Selective formation of (2E)-2-methylalk-2-enoates or 2-methyl alkanoates could be achieved in moderate to good yields under mild conditions via Sm/HOAc/EtOH system-mediated reduction of Baylis-Hillman acetates depending on the amount of samarium consumed in the reactions. Copyright Taylor & Francis Group, LLC.
Enantioselective hydrolysis of some 2-aryloxyalkanoic acid methyl esters and isosteric analogues using a penicillin G acylase-based HPLC monolithic silica column
Massolini, Gabriella,Calleri, Enrica,Lavecchia, Antonio,Loiodice, Fulvio,Lubda, Dieter,Temporini, Caterina,Fracchiolla, Giuseppe,Tortorella, Paolo,Novellino, Ettore,Caccialanza, Gabriele
, p. 535 - 542 (2007/10/03)
A technique based on liquid chromatography has been developed to facilitate studies of enantioselectivity in penicillin G acylase (PGA)-catalyzed hydrolysis of some 2-aryloxyalkanoic acid methyl esters and isosteric analogues. PGA was covalently immobilized on an aminopropyl monolithic silica support to create an immobilized HPLC-enzyme reactor. Two sets of experimental data were drawn to calculate the enantioselectivity (E) of the kinetically controlled enantiomer-differentiating reaction, the degree of substrate conversion and the enantiomeric excess of the product. The developed enzymatic reactor was coupled through a switching valve to an achiral analytical column for separation and quantitation of the hydrolysis products. The enantiomeric excess was determined off-line on a PGA-chiral stationary phase. In this way, highly precise E values were determined. A computational study related to the hydrolysis of the considered racemic esters was also carried out in order to unambiguously clarify both the substrate specificity and the enantioselectivity displayed by PGA.
Diastereoselective heterogeneous catalytic hydrogenation of Baylis- Hillman adducts
Mateus, Cristiano R.,Almeida, Wanda P.,Coelho, Fernando
, p. 2533 - 2536 (2007/10/03)
We describe herein our results concerning a highly diastereoselective heterogeneous hydrogenation of Baylis-Hillman adducts obtained from aromatic aldehydes. The results obtained are complementary to those already described for homogeneous catalytic hydro
Free-Radical Coupling of Alkyl and Aryl Halides with Electron-Deficient Alkenes Mediated by Chromium(II) Complexes
Tashtoush, Hasan I.,Sustmann, Reiner
, p. 1759 - 1762 (2007/10/02)
Free radicals generated from organic halides and (ethylenediamine)chromium(II) complexes in DMF are trapped by electron-deficient olefins.The coupling reactions of alkyl halides, described in Part I, are extended and, in addition, aryl halides are shown to be efficient radical precursors to yield coupling products in good yield. Key Words: Bond formation, C-C/ Chromium(II) complexes/ Radicals
