54512-75-3Relevant 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.
Pheromone synthesis. Part 243: Synthesis and biological evaluation of (3R,13R,1′S)-1′-ethyl-2′-methylpropyl 3,13-dimethylpentadecanoate, the major component of the sex pheromone of Paulownia bagworm, Clania variegata, and its stereoisomers
Mori, Kenji,Tashiro, Takuya,Zhao, Boguang,Suckling, David M.,El-Sayed, Ashraf M.
experimental part, p. 2642 - 2653 (2010/05/18)
All of the four stereoisomers of (1′S)-1′-ethyl-2′-methylpropyl 3,13-dimethylpentadecanoate, the major component of the female sex pheromone of Clania variegata, were synthesized by employing olefin cross metathesis as the key reaction and starting from (R)- or (S)-2-methyl-1-butanol, (R)- or (S)-citronellal, and (S)-2-methyl-3-pentanol. Their bioassay revealed the (3R,13R,1′S)-isomer as the bioactive one, whose more efficient synthesis was achieved in two different ways by employing Wittig reaction as the key step.
The chain carriers of intermolecular hydrogen abstraction in the photobromination with N-bromosuccinimide; modifications of the chain carriers
Zhang, Yu-Huang,Dong, Ming-Hua,Jiang, Xi-Kui,Chow, Yuan L.
, p. 1668 - 1675 (2007/10/02)
The photoinitiated bromination of 1-chloropentane with N-bromosuccinimide (NBS) in the presence of Br2 is compared with that of NBS and 1,1-dichloroethene to generate the succinimidyl radical (S radical) and with that of Br2 + K2CO3 to generate the bromine atom (Br radical) as the chain carriers.The relative reactivities of intermolecular H-abstraction (r-values) shown by the NBS + Br2 system decrease to levels lower than those shown by either S radical or Br radical chain propagations at lower temperatures under appropriate conditions: these observations indicate thepresence of a new chain propagating species that is assumed to be the bromine radical complex (BRC) modified from S radical or Br radical reversibly under the experimental conditions.Supporting evidence for the equilibria of S radical, Br radical, and BRC in the photodecomposition of NBS + Br2 is discussed.The unusual H-abstraction reactivity of Br radical toward the methyl hydrogens of 1-chloropentane was noted; this serves as independent support for the presence of a new radical propagation species.
