80-45-5Relevant 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.
Site-Selective Aliphatic C-H Chlorination Using N-Chloroamides Enables a Synthesis of Chlorolissoclimide
Quinn, Ryan K.,K?nst, Zef A.,Michalak, Sharon E.,Schmidt, Yvonne,Szklarski, Anne R.,Flores, Alex R.,Nam, Sangkil,Horne, David A.,Vanderwal, Christopher D.,Alexanian, Erik J.
supporting information, p. 696 - 702 (2016/02/03)
Methods for the practical, intermolecular functionalization of aliphatic C-H bonds remain a paramount goal of organic synthesis. Free radical alkane chlorination is an important industrial process for the production of small molecule chloroalkanes from simple hydrocarbons, yet applications to fine chemical synthesis are rare. Herein, we report a site-selective chlorination of aliphatic C-H bonds using readily available N-chloroamides and apply this transformation to a synthesis of chlorolissoclimide, a potently cytotoxic labdane diterpenoid. These reactions deliver alkyl chlorides in useful chemical yields with substrate as the limiting reagent. Notably, this approach tolerates substrate unsaturation that normally poses major challenges in chemoselective, aliphatic C-H functionalization. The sterically and electronically dictated site selectivities of the C-H chlorination are among the most selective alkane functionalizations known, providing a unique tool for chemical synthesis. The short synthesis of chlorolissoclimide features a high yielding, gram-scale radical C-H chlorination of sclareolide and a three-step/two-pot process for the introduction of the β-hydroxysuccinimide that is salient to all the lissoclimides and haterumaimides. Preliminary assays indicate that chlorolissoclimide and analogues are moderately active against aggressive melanoma and prostate cancer cell lines.
Process for preparation of oxyglutaric acid ester derivatives
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, (2008/06/13)
A process for preparing an oxyglutaric acid ester derivative of the formula: STR1 in which each of R1 and R2 is C1-5 alkoxy, C1-7 aralkyloxy, C7-9 halogenated aralkyloxy or phenyl, R4 is a hydroxyl-protecting group, and R5 is C1-10 alkyl which may have a substituent, comprises the steps of reacting a methyl phosphonate derivative or methyl phosphine oxide derivative with an oxyglutaric acid mono-ester to give a reaction product which comprises an oxyglutaric acid derivative having a phosphorus-containing group and a pentenedioic acid mono-ester (by-product), removing the pendenedioic acid mono-ester from the reaction product to isolate the oxyglutaric acid derivative, and converting the isolated oxyglutaric acid derivative into the oxyglutaric acid ester derivative. A process for obtaining an optically active oxyglutaric acid ester derivative is also disclosed.
Reduction of Sulfonic Acids and Related Organosulfur Compounds with Triphenylphosphine-Iodine System
Oae, Shigeru,Togo, Hideo
, p. 3802 - 3812 (2007/10/02)
Arenesulfonic acids, their sodium salts, and alkyl arenesulfonates can be reduced readily to the corresponding arenethiols quantitatively by treatment with a mixture of triphenylphosphine and a catalytic amount of iodine, while alkanesulfonic acids, sulfinic acids, disulfides, thiosulfonic S-esters, and sulfonates are also readily reduced to the corresponding thiols similarly.Upon treatment with a mixture of triphenylphosphine and excess iodine, however, these aliphatic sulfur compounds are converted eventually to the corresponding alkyl iodides.The relative reactivities of these sulfonyl derivatives in the reaction with the triphenylphosphine-iodine system are the following.Aromatic series: ArSO2Cl, ArSO2SAr' > ArSO2H > ArSO3R > ArSO3-HNBu3+ (or PyH+) > ArSO3H > ArSO2SO2Ar >> ArSO2CH2C(CH3)3, ArSO3Ar'.Aliphatic series: RSO2Cl, RSO2SR', RSO2-HNBu3+ > RSO3-HNBu3+ > RSSR, RSO2H > RSO3H > RSH > RSO3R'.In these reactions, the arenesulfonic acids bearing electron-donating substituents can be reduced more readily than those having electron-withdrawing substituents.
