- Benzylic Aroylation of Toluenes Mediated by a LiN(SiMe3)2/Cs+System
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Chemoselective deprotonative functionalization of benzylic C-H bonds is challenging, because the arene ring contains multiple aromatic C(sp2)-H bonds, which can be competitively deprotonated and lead to selectivity issues. Recently it was found that bimetallic [MN(SiMe3)2 M = Li, Na]/Cs+ combinations exhibit excellent benzylic selectivity. Herein, is reported the first deprotonative addition of toluenes to Weinreb amides mediated by LiN(SiMe3)2/CsF for the synthesis of a diverse array of 2-arylacetophenones. Surprisingly, simple methyl benzoates also react with toluenes under similar conditions to form 2-arylacetophenones without double addition to give tertiary alcohol products. This finding greatly increases the practicality and impact of this chemistry. Some challenging substrates with respect to benzylic deprotonations, such as fluoro and methoxy substituted toluenes, are selectively transformed to 2-aryl acetophenones. The value of benzylic deprotonation of 3-fluorotoluene is demonstrated by the synthesis of a key intermediate in the preparation of Polmacoxib.
- Gu, Yuanyun,Zhang, Zhen,Wang, Yan-En,Dai, Ziteng,Yuan, Yaqi,Xiong, Dan,Li, Jie,Walsh, Patrick J.,Mao, Jianyou
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supporting information
p. 406 - 418
(2022/01/14)
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- Copper-Catalyzed Three-Component Carboboronation of Allenes Using Highly Strained Cyclic Ketimines as Electrophiles
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A diastereoselective copper and NHC-ligand-catalyzed three-component difunctionalization of allenes with bis(pinacolato)diboron and 2H-azirines to afford borylated allylaziridines is described. The reaction exhibits complete diastereoselectivity and good yields, and the further chlorination of the corresponding borylated products was also performed. It is believed that the high ring-strain force of 2H-azirines facilitates the reaction. More chemical transformations of borylated allylaziridines are also reported.
- Deng, Hao,Dong, Yujie,Shangguan, Yu,Yang, Fazhou,Han, Sheng,Wu, Jiaqi,Liang, Bo,Guo, Hongchao,Zhang, Cheng
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supporting information
p. 4431 - 4435
(2021/05/26)
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- Oxaprozin Analogues as Selective RXR Agonists with Superior Properties and Pharmacokinetics
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The retinoid X receptors (RXR) are ligand-activated transcription factors involved in multiple regulatory networks as universal heterodimer partners for nuclear receptors. Despite their high therapeutic potential in many pathologies, targeting of RXR has only been exploited in cancer treatment as the currently available RXR agonists suffer from exceptional lipophilicity, poor pharmacokinetics (PK), and adverse effects. Aiming to overcome the limitations and to provide improved RXR ligands, we developed a new potent RXR ligand chemotype based on the nonsteroidal anti-inflammatory drug oxaprozin. Systematic structure-activity relationship analysis enabled structural optimization toward low nanomolar potency similar to the well-established rexinoids. Cocrystal structures of the most active derivatives demonstrated orthosteric binding, and in vivo profiling revealed superior PK properties compared to current RXR agonists. The optimized compounds were highly selective for RXR activation and induced RXR-regulated gene expression in native cellular and in vivo settings suggesting them as excellent chemical tools to further explore the therapeutic potential of RXR.
- Schierle, Simone,Chaikuad, Apirat,Lillich, Felix F.,Ni, Xiaomin,Woltersdorf, Stefano,Schallmayer, Espen,Renelt, Beatrice,Ronchetti, Riccardo,Knapp, Stefan,Proschak, Ewgenij,Merk, Daniel
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supporting information
p. 5123 - 5136
(2021/05/04)
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- Palladium-catalyzed synthesis of α-aryl acetophenones from styryl ethers and aryl diazonium saltsviaregioselective Heck arylation at room temperature
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Preparation of α-aryl acetophenones from styryl ethers and aryldiazonium salts is described. The reaction is catalyzed by palladium acetate at room temperature in the absence of ligand and base. The developed method is highly attractive in terms of reaction conditions, substrate scope, functional group tolerance and yields. Synthetic applications of the present method are demonstrated by preparing α-aryl indoles and 3-aryl isocoumarin from styryl ethers.
- Kandasamy, Jeyakumar,Lee, Yong Rok,Singh, Adesh Kumar,Venkatesh, Rapelly
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supporting information
p. 7832 - 7837
(2021/09/28)
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- Ruthenium(II)-Catalyzed Cross-Coupling of Benzoyl Formic Acids with Toluenes: Synthesis of 2-Phenylacetophenones
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Herein, we report a direct method to synthesize 2-phenylacetophenone through a ruthenium(II)-catalyzed cross-coupling reaction between acyl and benzyl radical. The various derivatives of 2-phenylacetophenone were prepared easily in moderate to good yields. These reactions provide a straightforward pathway to synthesize a variety of ketones bearing various functional groups.
- Chen, Yujie,Dai, Chenyang,Huang, Zhibin,Jiang, Yaqiqi,Shu, Sai,Yang, Shan,Zhao, Yingsheng
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p. 2955 - 2961
(2021/07/22)
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- The organocatalytic enantiodivergent fluorination of β-ketodiaryl-phosphine oxides for the construction of carbon-fluorine quaternary stereocenters
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Commercially available cinchona alkaloids that can catalyze the enantiodivergent fluorination of β-ketodiarylphosphine oxides were developed to construct carbon-fluorine quaternary stereocenters. This protocol features a wide scope of substrates and excellent enantioselectivities, and it is scalable.
- Xie, Shaolei,He, Zhi-Juan,Zhang, Ling-Hui,Huang, Bo-Lun,Chen, Xiao-Wei,Zhan, Zong-Song,Zhang, Fu-Min
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p. 2069 - 2072
(2021/03/01)
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- Two-Step One-Pot Synthesis of Unsymmetrical (Hetero)Aryl 1,2-Diketones by Addition-Oxygenation of Potassium Aryltrifluoroborates to (Hetero)Arylacetonitriles
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An efficient one-pot two-step procedure for the synthesis of unsymmetrical (hetero)aryl 1,2-diketones has been developed. The reaction proceeds through a palladium-catalyzed nucleophilic addition of potassium aryltrifluoroborates to aliphatic nitriles followed by a copper-catalyzed aerobic benzylic C–H oxygenation using molecular oxygen as a green oxidant. This represents the first example of the direct synthesis of unsymmetrical diaryl 1,2-diketones from arylacetonitriles. This method utilizes inexpensive, stable, nontoxic, and readily available starting materials, is highly effective in the presence of both electron-rich and electron-poor nitriles and aryltrifluoroborates, and tolerates a wide variety of functional groups. The synthetic utility of this transformation was shown by increasing the scale of the reaction and by carrying out the one-pot protocol for the preparation of quinoxaline and benzimidazole derivatives. A plausible reaction mechanism has also been proposed.
- Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
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p. 494 - 505
(2018/02/09)
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- Metal-free synthesis of ketones by visible-light induced aerobic oxidative radical addition of aryl hydrazines to alkenes
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A green and cost-effective method has been developed for the conversion of alkenes to ketones under metal-free conditions. The reaction involves the oxidative addition of alkenes with aryl radicals, which are generated by visible-light induced aerobic oxidation of arylhydrazines. The key features of this reaction include broad substrate scope, readily available reagents and amenability to gram-scale synthesis.
- Ding, Ya,Zhang, Wenkai,Li, Hao,Meng, Yunge,Zhang, Te,Chen, Qiu-Yun,Zhu, Chunyin
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supporting information
p. 2941 - 2944
(2017/07/24)
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- Palladium-Catalyzed Chemo- and Enantioselective C?O Bond Cleavage of α-Acyloxy Ketones by Hydrogenolysis
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A chemoselective C?O bond cleavage of the ester alkyl side-chain of α-acyloxy ketones was realized for the first time by a highly efficient palladium-catalyzed hydrogenolysis (S/C=6000, the highest catalytic efficiency by far). Furthermore, a kinetic resolution of α-acyloxy ketones was first developed by enantioselective hydrogenolysis with good yields and up to 99 % ee.
- Chen, Jianzhong,Zhang, Zhenfeng,Liu, Delong,Zhang, Wanbin
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supporting information
p. 8444 - 8447
(2016/07/19)
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- Visible Light Mediated Reductive Cleavage of C-O Bonds Accessing α-Substituted Aryl Ketones
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C-O σ-bonds in multifaceted benzoin derivatives can be effectively cleaved as acetates using catalytic amounts of [Ru(bpy)3]Cl2 as photoredox catalyst in combination with Hantzsch ester and triethylamine as a sacrificial electron donor. This mild and operationally simple method is applicable to a great variety of substrates. Homo- and cross-benzoins, which are easily accessed by NHC (N-heterocyclic carbene) catalysis, with both electron-withdrawing and electron-donating substituents, including aryl halogenides, can be employed. The deoxygenated counterparts are isolated in good to excellent yields. These broadly accessible, α-substituted (nonsymmetric) aryl ketones are versatilely applicable for further transformations as illustrated by the syntheses of 2-arylbenzofurans.
- Speckmeier, Elisabeth,Padié, Clément,Zeitler, Kirsten
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supporting information
p. 4818 - 4821
(2015/10/12)
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- NOVEL DIHYDROPYRIMIDIN-2(1H)-ONE COMPOUNDS AS S-NITROSOGLUTATHIONE REDUCTASE INHIBITORS
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The present invention is directed to novel dihydropyrimidin-2(1H)-one compounds useful as S-nitrosoglutathione reductase (GSNOR) inhibitors, pharmaceutical compositions comprising such compounds, and methods of making and using the same.
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Page/Page column 139
(2011/04/24)
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- Preparation of functionalized organomanganese(II) reagents by direct insertion of manganese to aromatic and benzylic halides
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Functionalized arylmanganese compounds were prepared using commercial manganese powder in the presence of LiCl and catalytic amounts of both 2.5% InCl3 and 2.5% PbCl2 (THF, 0-50 °C). In addition, benzylic manganese reagents are obtained at 25 °C in ca. 70-80% yield (in the absence of LiCl) using commercial manganese powder and catalytic amounts of 2.5% InCl3 and 2.5% PbCl2. The resulting organomanganese reagents undergo smooth 1,2-addition, acylation, allylic substitution, Pd-catalyzed cross-coupling, and copper-catalyzed conjugate addition, affording the desired products in good yields.
- Peng, Zhihua,Knochel, Paul
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supporting information; experimental part
p. 3198 - 3201
(2011/08/06)
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- Pd-catalyzed synthesis of α-aryl ketones through couplings of α-arylacetyl chlorides with triarylbismuths as multi-coupling nucleophiles
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The cross-coupling reaction of α-arylacetyl chlorides with triarylbismuths was studied under Pd-catalyzed conditions. The reaction was found to be facile under the established protocol and furnished high yields of α-aryl ketones in short reaction times. T
- Rao, Maddali L.N.,Giri, Somnath,Jadhav, Deepak N.
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experimental part
p. 6133 - 6138
(2010/02/27)
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- TiCl4-catalyzed indirect anti-Markovnikov hydration of alkynes: Application to the synthesis of benzo[b]furans
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(Chemical Equation Presented) An efficient methodology for the indirect anti-Markovnikov hydration of unsymmetrically substituted terminal and internal alkynes is based on TiCl4-catalyzed hydroamination reactions. Its application to ortho-alkynylhaloarenes, followed by a copper-catalyzed O-arylation, provides flexible access to substituted benzo[b]furans.
- Ackermann, Lutz,Kaspar, Ludwig T.
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p. 6149 - 6153
(2008/02/09)
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- THERAPEUTIC FLUOROETHYL UREAS
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Compounds of the formula or a pharmaceutically acceptable salt thereof or a tautomer thereof, wherein A and B are as described herein, are useful for treating conditions afflicting mammals.
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Page/Page column 10
(2008/06/13)
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- Nickelacycles with anionic C-N-N′ terdentate ligands containing (5,5), (5,6), (5,7) and (6,5) membered fused rings. Reaction with ethylene
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A series of nickelacycle complexes with di-Schiff bases acting as terdentate CNN- anionic ligands has been prepared. Oxidative addition of one C-X bond in mono- or di-ortho-halogenoaryl substituted ligands, N,N′-dibenzylidene-alkane-1,2-diamines (ethane, propane and butanediamines) and N,N′-bis(1,2-diphenylethylidene)ethane-1,2-diamine, to [Ni(cod)2] gives neutral complexes [NiX(CNN)] containing (5,5), (5,6), (5,7) and (6,5)-membered fused chelate rings (NiCN and NiNN respectively). Complexes from monohalogenoaryl substituted ligands are obtained as mixtures of two non-interchanging configurational isomers (E or Z stereochemistry about the non-metallated imine group). Cationic complexes [NiL(CNN)]BF4 are generated by halide abstraction from these neutral complexes by using TlBF4 and 2,4,6-Me3C5H2N or CH3CN as stabilizing ligand. In ionic compounds from monohalogenoaryl substituted ligands the formation of isomers by restricted rotation around the Cphenyl-Cmethinic bond is also observed. The 1H NMR spectra of complexes with (5,5), (5,6), (6,5) fused rings show fluxional behavior, the data being consistent with interconversion of two chelate ring conformations that are associated with the relative position of the non-metallated methinic moiety in the lower or the upper side of the coordination plane. Molecular structures of three ionic complexes [Ni(2,4,6-Me3C5H2N)(CNN)]BF4, were determined by X-ray single-crystal diffraction, revealing the effects of chelate sizes on the distortion of the coordination sphere around nickel. Ionic complexes [Ni(CH3CN)(CNN)]BF4 were tested as precursors of active species in the reaction with ethylene under pressure. The influence of the nickelacycle ring size on the insertion reaction is discussed, with moderate activities being observed only when the Ni-C bond is involved in a six-membered ring.
- Ceder,Muller,Ordinas,Maestro,Mahia,Bardia,Solans
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p. 977 - 985
(2007/10/03)
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