- Chiral Metal Salts as Ligands for Catalytic Asymmetric Mannich Reactions with Simple Amides
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Catalytic asymmetric Mannich reactions of imines with weakly acidic simple amides were developed using a chiral potassium hexamethyldisilazide (KHMDS)-bis(oxazoline) potassium salt (K-Box) catalyst system. The desired reactions proceeded to afford the tar
- Yamashita, Yasuhiro,Noguchi, Aika,Fushimi, Seiya,Hatanaka, Miho,Kobayashi, Shū
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supporting information
p. 5598 - 5604
(2021/05/06)
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- Entropic Mixing Allows Monomeric-Like Absorption in Neat BODIPY Films
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Intermolecular interactions play a crucial role in materials chemistry because they govern thin film morphology. The photophysical properties of films of organic dyes are highly sensitive to the local environment, and a considerable effort has therefore been dedicated to engineering the morphology of organic thin films. Solubilizing side chains can successfully spatially separate chromophores, reducing detrimental intermolecular interactions. However, this strategy is also significantly decreasing achievable dye concentration. Here, five BODIPY derivatives containing small alkyl chains in the α-position were synthesized and photophysically characterized. By blending two or more derivatives, the increase in entropy reduces aggregation and therefore produces films with extreme dye concentration and, at the same time almost solution like absorption properties. Such a film was placed inside an optical cavity and the achieved system was demonstrated to reach the strong exciton-photon coupling regime by virtue of the achieved dye concentration and sharp absorption features of the film.
- Sch?fer, Clara,Mony, Jürgen,Olsson, Thomas,B?rjesson, Karl
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supporting information
p. 14295 - 14299
(2020/10/06)
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- High-Throughput Ligand Screening Enables the Enantioselective Conjugate Borylation of Cyclobutenones to Access Synthetically Versatile Tertiary Cyclobutylboronates
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Cyclobutane rings are important in medicinal chemistry, yet few enantioselective methods exist to access this scaffold. In particular, cyclobutylboronates are receiving increasing attention in the literature due to the synthetic versatility of alkylboronic esters and the increasing role of boronic acids in drug discovery. Herein, a conjugate borylation of α-alkyl,β-aryl/alkyl cyclobutenones is reported leading to the first synthesis of enantioenriched tertiary cyclobutylboronates. Cyclobutanones with two stereogenic centers are obtained in good to high yield, with high enantioselectivity and diastereoselectivity. Vital to this advance are the development of a novel approach to α,β unsymmetrically disubstituted cyclobutenone substrates and the use of a high-throughput chiral ligand screening platform. The synthetic utility of both the boronic ester and ketone functionalities is displayed, with remarkable chemoselectivity for either group being possible in this small ring scaffold.
- Clement, Helen A.,Boghi, Michele,McDonald, Rory M.,Bernier, Louise,Coe, Jotham W.,Farrell, William,Helal, Christopher J.,Reese, Matthew R.,Sach, Neal W.,Lee, Jack C.,Hall, Dennis G.
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supporting information
p. 18405 - 18409
(2019/11/16)
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- Catalytic Enantioselective α-Fluorination of 2-Acyl Imidazoles via Iridium Complexes
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The first highly enantioselective α-fluorination of 2-acyl imidazoles utilizing iridium catalysis has been accomplished. This transformation features mild conditions and a remarkably broad substrate scope, providing an efficient and highly enantioselective approach to obtain a wide range of fluorine-containing 2-acyl imidazoles which are found in a variety of bioactive compounds and prodrugs. A large scale synthesis has also been tested to demonstrate the potential utility of this fluorination method.
- Xu, Guo-Qiang,Liang, Hui,Fang, Jie,Jia, Zhi-Long,Chen, Jian-Qiang,Xu, Peng-Fei
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supporting information
p. 3355 - 3358
(2016/12/09)
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- Supported Gold Nanoparticles for Efficient α-Oxygenation of Secondary and Tertiary Amines into Amides
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Although the α-oxygenation of amines is a highly attractive method for the synthesis of amides, efficient catalysts suited to a wide range of secondary and tertiary alkyl amines using O2as the terminal oxidant have no precedent. This report describes a novel, green α-oxygenation of a wide range of linear and cyclic secondary and tertiary amines mediated by gold nanoparticles supported on alumina (Au/Al2O3). The observed catalysis was truly heterogeneous, and the catalyst could be reused. The present α-oxygenation utilizes O2as the terminal oxidant and water as the oxygen atom source of amides. The method generates water as the only theoretical by-product, which highlights the environmentally benign nature of the present reaction. Additionally, the present α-oxygenation provides a convenient method for the synthesis of18O-labeled amides using H218O as the oxygen source.
- Jin, Xiongjie,Kataoka, Kengo,Yatabe, Takafumi,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 7212 - 7217
(2016/07/06)
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- Chemo- and Stereoselective Transition-Metal-Free Amination of Amides with Azides
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The synthesis of α-amino carbonyl/carboxyl compounds is a contemporary challenge in organic synthesis. Herein, we present a stereoselective α-amination of amides employing simple azides that proceeds under mild conditions with release of nitrogen gas. The
- Tona, Veronica,De La Torre, Aurélien,Padmanaban, Mohan,Ruider, Stefan,González, Leticia,Maulide, Nuno
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supporting information
p. 8348 - 8351
(2016/07/26)
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- Palladium-Catalyzed Aminocarbonylation of Aliphatic Alkenes with N,N-Dimethylformamide as an in Situ Source of CO
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The palladium-catalyzed aminocarbonylation of aliphatic alkenes is presented for the first time without the need for external CO pressure. N,N-dimethylformamide (DMF) is used as an in situ source of both the required carbon monoxide and the amine substrate. The applied palladium catalytic system is well-known for a number of carbonylation reactions, including those with CO surrogates and tandem isomerizing carbonylations. The reaction pathway was investigated and proved to proceed by an acid-catalyzed DMF decomposition to CO and dimethyl amine with subsequent aminocarbonylation of the alkene. Pressure-versus-time curves gave more insight into the correlation between acid concentration and aminocarbonylation activity. Aliphatic alkenes (terminal and internal) are transformed, also in commercial glassware, into the corresponding linear N,N-dimethylamides with excellent selectivities. Hence, amide synthesis by aminocarbonylation moves closer to application in standard organic laboratories. Do-it-yourself CO production: The aminocarbonylation of alkenes for aliphatic amide synthesis is presented for the first time using N,N-dimethylamine as an in situ source of both, the required CO and dimethylamine. Excellent selectivities to the linear product are ensured by isomerizing carbonylation applying a [Pd]/1,2-DTBPMB system. 1,2-DTBPMB=1,2-bis((di-tert-butylphos- phino)methyl)benzene.
- Seidensticker, Thomas,Furst, Marc R. L.,Frauenlob, Robin,Vondran, Johanna,Paetzold, Eckhard,Kragl, Udo,Vorholt, Andreas J.
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p. 4085 - 4090
(2016/01/09)
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- Bromination of enamines from tertiary amides using the petasis reagent: A convenient one-pot regioselective route to bromomethyl ketones
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An original one-pot synthesis of bromomethyl ketones is achived using the Petasis reagent (dimethyltitanocene) as a key for enamine generation. Several amides were used to test the limits of the procedure by changing either the alkyl chain R or the amino portion of the starting materials. The enamines generated in situ were allowed to react with bromine at low temperature followed by hydrolysis to yield bromomethyl ketones in excellent yields (85 to 95%). Mechanistic details and optimum conditions for the reaction are briefly discussed. The present approach offers several advantages such as regioselectivity in enamine formation, good yields, mild reaction conditions, and ease of experimentation.
- Kobeissi, Marwan,Cherry, Khalil,Jomaa, Wissam
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supporting information
p. 2955 - 2965
(2013/09/02)
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- Indazole compounds, pharmaceutical compositions and use
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The invention provides a series of novel heterocyclic amides of the formula I in which the group A CRa can be --CRb=CRa--, --CHRb--CHRa-- or --N=CRa--, the amidic group Re.L can be Re.X.CO.NH, Re.X.CS.NH or Re.NH.CO attached at position 4, 5 or 6 of the benzenoid moiety, Z is an acid group selected from the group consisting of carboxy, an acylsulphonamide residue of the formula CO.NH.SOn Rg and a tetrazolyl residue of the formula II, and the radicals Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, n, X, G1, Q and G2 have the meanings defined in the following specification. The compounds of formula I are leukotriene antagonists. The invention also provides pharmaceutically acceptable salts of the formula I compounds; pharmaceutical compositions containing the formula I compounds, or their salts, for use in the treatment of, for example, allergic or inflammatory diseases, or endotoxic or traumatic shock conditions; and processes for the manufacture of the formula I compounds, as well as intermediates for use in such manufacture.
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