- Gram-Scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles
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A series of acyl fluorides was synthesized at 100 mmol scale using phase-transfer-catalyzed halogen exchange between acyl chlorides and aqueous bifluoride solution. The convenient procedure consists of vigorous stirring of the biphasic mixture at room temperature, followed by extraction and distillation. Isolated acyl fluorides (usually 7-20 g) display excellent purity and can be transformed into sterically hindered amides and esters when treated with lithium amide bases and alkoxides under mild conditions.
- Tryniszewski, Micha?,Barbasiewicz, Micha?
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p. 1446 - 1460
(2021/11/30)
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- Palladium-catalyzed Suzuki-Miyaura coupling of amides by carbon-nitrogen cleavage: General strategy for amide N-C bond activation
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The first palladium-catalyzed Suzuki-Miyaura cross-coupling of amides with boronic acids for the synthesis of ketones by sterically-controlled N-C bond activation is reported. The transformation is characterized by operational simplicity using bench-stable, commercial reagents and catalysts, and a broad substrate scope, including substrates with electron-donating and withdrawing groups on both coupling partners, steric-hindrance, heterocycles, halides, esters and ketones. The scope and limitations are presented in the synthesis of >60 functionalized ketones. Mechanistic studies provide insight into the catalytic cycle of the cross-coupling, including the first experimental evidence for Pd insertion into the amide N-C bond. The synthetic utility is showcased by a gram-scale cross-coupling and cross-coupling at room temperature. Most importantly, this process provides a blueprint for the development of a plethora of metal catalyzed reactions of typically inert amide bonds via acyl-metal intermediates. A unified strategy for amide bond activation to enable metal insertion into N-C amide bond is outlined (Scheme 1).
- Meng, Guangrong,Szostak, Michal
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supporting information
p. 5690 - 5707
(2016/07/06)
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- Lewis acid-catalyzed oxidation of benzylamines to benzamides
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A novel Lewis acid-catalyzed oxidation of benzylamines to the corresponding amides has been developed. Using 10 mol% of ZnBr2 or FeCl 3 as the catalyst and TBHP as the oxidant, amides were produced under mild conditions. The Royal Society of Chemistry 2012..
- Wu, Xiao-Feng,Bheeter, Charles Beromeo,Neumann, Helfried,Dixneuf, Pierre H.,Beller, Matthias
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supporting information
p. 12237 - 12239
(2013/01/16)
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- 2-Cyanophenylboronic Acid or Ester Thereof in Which Impurities Are Decreased, and Production Method Thereof
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A method for producing high-purity 2-cyanophenylboronic acid, characterized by reacting benzonitrile, lithium 2,2,6,6-tetramethylpiperidide, and trialkoxyborane, adding an aqueous acidic solution to a reaction solution containing the obtained 2-cyanophenylboronic acid, carrying out a contact treatment at a pH of below 7 in the presence of a water-immiscible organic solvent, and then obtaining the 2-cyanophenylboronic acid from the organic layer.
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Page/Page column 4-5
(2009/07/25)
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- Intermolecular dearomatising addition of organolithium compounds to N-benzoylamides of 2,2,6,6-tetramethylpiperidine
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N-Benzoylamides of 2,2,6,6-tetramethylpiperidine are not ortholithiated by organolithium compounds but instead undergo nucleophilic addition of the organolithium compound to the aromatic ring in the manner of a conjugate addition. The resulting dearomatised enolates may be protonated or alkylated, and yield substituted cyclohexadienes in yields of up to 76%. Deprotection of the piperidine ring is possible under acidic conditions. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Clayden, Jonathan,Foricher, Yann J. Y.,Lam, Ho Kam
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p. 3558 - 3565
(2007/10/03)
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- Carbolithiation of aromatic rings: Cyclohexadienes from N-aroyl-2,2,6,6-tetramethylpiperidines
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Benzamides whose nitrogen atom is part of a 2,2,6,6-tetramethylpiperidine ring are dearomatised by alkyllithiums, which attack them regioselectively to yield, after electrophilic quench, substituted cyclohexadienes.
- Clayden, Jonathan,Foricher, Yann J. Y.,Lam, Ho Kam
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p. 2138 - 2139
(2007/10/03)
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- Synthesis of Ortho Substituted Arylboronic Esters by in Situ Trapping of Unstable Lithio Intermediates
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matrix presented Ortho lithiation-in situ boration using lithium 2,2,6,6-tetramethylpiperidide (LTMP) in combination with triisopropylborate (B(OiPr)3) is a highly efficient and experimentally straightforward process for the preparation of ortho substituted arylboronic esters. The mild reaction conditions allow the presence of functionalities such as ester or cyano groups or halogen substituents that are usually not compatible with the conditions used in directed ortho metalation of arenes. The arylboronic esters underwent Suzuki-type cross-coupling with a range of aryl halides, furnishing biaryls in 53-94% yield.
- Kristensen, Jesper,Lysen, Morten,Vedso, Per,Begtrup, Mikael
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p. 1435 - 1437
(2007/10/03)
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- Conformational Studies by Dynamic Nuclear Magnetic Resonance. Part 17. Stereodynamic Processes in Hindered Piperidyl-amides and -amidines
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It has been shown that molecules containing hindered piperidyl rings can have planar or perpendicular conformations depending on the functional group attached to nitrogen.In addition, we have shown that when the group is CR=NPh (amidines) the molecule may
- Lunazzi, Lodovico,Macciantelli, Dante,Tassi, Danilo,Dondoni, Alessandro
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p. 717 - 723
(2007/10/02)
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