- Catalytic α-Deracemization of Ketones Enabled by Photoredox Deprotonation and Enantioselective Protonation
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This study reports the catalytic deracemization of ketones bearing stereocenters in the α-position in a single reaction via deprotonation, followed by enantioselective protonation. The principle of microscopic reversibility, which has previously rendered this strategy elusive, is overcome by a photoredox deprotonation through single electron transfer and subsequent hydrogen atom transfer (HAT). Specifically, the irradiation of racemic pyridylketones in the presence of a single photocatalyst and a tertiary amine provides nonracemic carbonyl compounds with up to 97% enantiomeric excess. The photocatalyst harvests the visible light, induces the redox process, and is responsible for the asymmetric induction, while the amine serves as a single electron donor, HAT reagent, and proton source. This conceptually simple light-driven strategy of coupling a photoredox deprotonation with a stereocontrolled protonation, in conjunction with an enrichment process, serves as a blueprint for other deracemizations of ubiquitous carbonyl compounds.
- Chen, Shuming,Gao, Anthony Z.,Ivlev, Sergei I.,Meggers, Eric,Nie, Xin,Ye, Chen-Xi,Zhang, Chenhao
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supporting information
p. 13393 - 13400
(2021/09/03)
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- para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
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Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
- Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
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p. 5058 - 5061
(2020/05/18)
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- Preparation method of para-substituted aryl compound
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The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
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- Design of noncompetitive interleukin-8 inhibitors acting on CXCR1 and CXCR2
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Chemokines CXCL8 and CXCL1 play a key role in the recruitment of neutrophils at the site of inflammation. CXCL8 binds two membrane receptors, CXCR1 and CXCR2, whereas CXCL1 is a selective agonist for CXCR2. In the past decade, the physiopathological role of CXCL8 and CXCL1 has been investigated. A novel class of small molecular weight allosteric CXCR1 inhibitors was identified, and reparixin, the first drug candidate, is currently under clinical investigation in the prevention of ischemia/reperfusion injury in organ transplantation. Reparixin binding mode to CXCR1 has been studied and used for a computer-assisted design program of dual allosteric CXCR1 and CXCR2 inhibitors. In this paper, the results of modeling-driven SAR studies for the identification of potent dual inhibitors are discussed, and three new compounds (56, 67, and 79) sharing a common triflate moiety have been selected as potential leads with optimized pharmacokinetic characteristics.
- Moriconi, Alessio,Cesta, Maria Candida,Cervellera, Maria Neve,Aramini, Andrea,Coniglio, Silvia,Colagioia, Sandro,Beccari, Andrea Rosario,Bizzarri, Cinzia,Cavicchia, Michela Rita,Locati, Massimo,Galliera, Emanuela,Di Benedetto, Paola,Vigilante, Paolo,Bertini, Riccardo,Allegretti, Marcello
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p. 3984 - 4002
(2008/02/11)
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- A novel asymmetric synthesis of tritium and carbon-14 labeled (R)-ibuprofen
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An efficient asymmetric synthesis of tritium and carbon-14 labeled R-ibuprofen was achieved in good overall yield (15% and 47%, respectively) and excellent enantiomerical excess (>98% e.e.), using (4R, 5S)-4-methyl-5- phenyl-2-oxazolidinone as a chiral au
- Zhang, Yinsheng,Hong, Yang,Huang, Che C.,Belmont, Daniel
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p. 237 - 244
(2007/10/03)
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- Enantioselective syntheses of 2-arylpropanoic acid non-steroidal antiinflammatory drugs and related compounds
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(S)-2-[4′-(2″-Methylpropyl)phenylpropanoic acid (ibuprofen) and (S)-2-(3′-benzoylphenyl)propanoic acid (ketoprofen) have been synthesised in high enantiomeric excess. Control of stereochemistry was achieved by a combination of Sharpless epoxidalion followed by catalytic hydrogenolysis of the introduced benzylic epoxide oxygen bond. Also, the coupling of organic compounds in the presence of palladium with enantiopure 2-(3-iodophenyl)propanoic and 2-(4-iodophenyl)propanoic acids, prepared by the methodology above, is a general method for the synthesis of optically active arylpropanoic acids.
- Hamon, David P.G.,Massy-Westropp, Ralph A.,Newton, Josephine L.
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p. 12645 - 12660
(2007/10/02)
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- Synthesis of Arylpropanoic Acids From Optically Active 2-(Iodophenyl)propanoic Acids
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The coupling of organozinc compounds with homochiral 2-(3-iodophenyl)propanoic and 2-(4-iodophenyl)propanoic acids in the presence of palladium is a general method for the synthesis of optically active arylpropanoic acids.
- Hamon, David P. G.,Massy-Westropp, Ralph A.,Newton, Josephine L.
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p. 5333 - 5336
(2007/10/02)
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