76475-07-5Relevant articles and documents
Practical and Selective sp3 C?H Bond Chlorination via Aminium Radicals
McMillan, Alastair J.,Sieńkowska, Martyna,Di Lorenzo, Piero,Gransbury, Gemma K.,Chilton, Nicholas F.,Salamone, Michela,Ruffoni, Alessandro,Bietti, Massimo,Leonori, Daniele
supporting information, p. 7132 - 7139 (2021/03/03)
The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp3 C?H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp3 C?H chlorination.
MECHANISMS OF FREE-RADICAL REACTIONS. XXIV. QUANTITATIVE DESCRIPTION OF THE POLAR EFFECTS OF SUBSTITUENTS ON THE KINETICS OF THE FREE-RADICAL CHLORINATION OF ALIPHATIC COMPOUNDS BY N-CHLOROPIPERIDINE
Dneprovskii, A. S.,Mil'tsov, S. A.,Arbuzov, P. V.
, p. 1826 - 1835 (2007/10/02)
The free-radical chlorination of 1-substituted alkanes with electron-withdrawing substituents by N-chloropiperidine in trifluoroacetic acid was studied by the method of competing reactions, and the relative rate constants were obtained for all positions of the substrates.The data on the position selectivity can be described satisfactorily by means of an electrostatic model of the polar effect of the substituent, calculated according to the Kirkwood-Westheimer equation.The obtained characteristics of the electrostatic effect can be successfully applied to calculation of the substrate selectivity and the intermolecular relative rate constants for all the positions, beginning with the third.The Taft equation is unsuitable for description of the effect of substituents on the reaction rate.
Free Radical Substitution. Part 38. The Effect of Solvent on the Atomic Chlorination and Bromination of 2-Substituted Butanes and the Importance of Steric Effects
Atto, Saeed Y.,Tedder, John M.,Walton, John C.
, p. 629 - 634 (2007/10/02)
The relative selectivity of atomic halogenation of 2-substituted butanes is influenced by the phase and by solvents.There are solvents which increase the selectivity compared with the gas phase and solvents which decrease the relative selectivity.However the most striking feature of the halogenation (especially the bromination) of 2-substituted butanes is the high reactivity of the 2-position notwithstanding very unfavourable polar effects.This reactivity is attributed to the release of steric compression associated with the abstraction of the tertiary hydrogen atom.The halogenation of butan-2-ol esters is associated with some decomposition of 2-butyl radical (OCOR)CH3> and the chlorination of 2-phenylbutane with the formation of olefins 2-phenylbut -1-ene and 2-phenylbut-2-ene.
Chlorination of Carboxylic Acid Derivatives. IX. Liquid Phase Chlorination of Aliphatic C2-C8 Alkyl Acetates. EI Mass Spectra of Monochlorinated Esters
Korhonen, Ilpo O. O.
, p. 39 - 46 (2007/10/02)
A series of aliphatic alkyl acetates from ethyl to octyl acetate was chlorinated in the liquid phase in order to obtain monochlorinated products.The chlorination of esters was carried out with chlorine in the liquid phase in the absence and in the presence of benzene and with sulfuryl chloride in the presence of Bz2O2.The products were determined by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry.Chlorination is appreciably deactivated at the 1-position, particularly with SO2Cl2, the deactivation at the 2-position being strongest with Cl2 in the presence of benzene.The amounts of 1-chloro and ω-chloro isomers constituted the greatest disparity between the chlorination methods.The most characteristic mass spectral fragment ions of the 35 chlorinated alkyl acetates are given.
Reactions du n=chloroparatoluenesulfonamidate de sodium (chloramine t) sur les olefines en miliu acide organique
Damin, Bernard,Garapon, Jacques,Sillion, Bernard
, p. 1709 - 1710 (2007/10/02)
Vic. chloro-acetoxy and vic. chloro-tosylamino alcanes are the main products of the electrophilic reaction of chloramine T on olefins in acetic acid. The stereochemistry of the acetoxy chloration of the 2-butenes and cyclohexene is trans.
