1073-35-4Relevant academic research and scientific papers
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.
The Regio- and Stereoselectivity of Radical Chlorination of Cycloalkanes with Different Halogen Carriers and Host-Guest Complexes
Schneider, Hans-Joerg,Philippi, Klaus
, p. 3056 - 3074 (2007/10/02)
The reaction of trans-1,4-dimethylcyclohexane (1) with (dichloroiodo)benzene (D), with most of the p-substituted D-derivatives, and with chlorine in carbon disulfide shows a regioselectivity of Rts ca. 10; reactions with o-substituted D-compounds or with D (R=H) in acetic acid or water show appreciable conversion, but lower selectivities of Rts ca. 5.Tertiary cyclohexyl radicals are chlorinated preferentially from the axial side with D (R=H); ortho-substituents in D, or replacement of CCl4 by CS2 or benzene lead to lower stereoselectivities.Chlorinations with iodophenyl derivatives, which are bound to a steroid matrix, exhibit no significant change in regioselectivity; the same is observed for reactions with chlorine in the presence of newly synthesized macrocyclic azacyclophane salts in water, although these form inclusion complexes with the hydrocarbons used and inhibit the hydrolysis of chlorides obtained from tetralin. α-Cyclodextrin, however, leads by selective complexation of 1 to selective chlorination of the primary C-H bonds.Syntheses and 13C NMR shifts of the azacyclophanes are described.
