- Effect of a phosphazene base on the diastereoselectivity of addition of α-sulfonyl carbanions to butyraldehyde and isopropylideneglyceraldehyde
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The effect of tBuP4, a strong and cation-free base, on the yield and diastereoselectivity of additions of thus formed "naked" α-sulfonyl carbanions to achiral butyraldehyde and chiral isopropylideneglyceraldehyde was studied. It has been found that with tBuP4 a reasonable yield (~55%) and a slightly better diastereoselectivity (72% of the anti diastreomer) are obtained with achiral and nonfunctionalized butyraldehyde while with isopropylideneglyceraldehyde the use of tBuP4 allowed us to greatly increase the yields (up to 95-100%) and the diastereoselectivities (83-89% of a single diastereomer over the four possible diastereomers). It was also shown that the extra oxygen atom in the α-position plays a determinant role in this effect.
- Solladie-Cavallo, Ariette,Roche, Didier,Fischer, Jean,De Cian, Andre
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Read Online
- Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
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The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
- Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
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supporting information
p. 2652 - 2657
(2021/04/21)
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- COMPOSITIONS AND METHODS OF TARGETING MUTANT K-RAS
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Compounds and compositions are presented that inhibit K-Ras, and especially mutant K-Ras. Certain compounds preferentially or even selectively inhibit specific forms of mutant K-Ras, and particularly the G12D mutant form.
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Paragraph 0076; 0077
(2018/08/03)
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- Conversion of alcohols to alkyl esters and carboxylic acids using heterogeneous palladium-based catalysts
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Disclosed are methods for synthesizing an ester or a carboxylic acid from an organic alcohol. To form the ester one reacts, in the presence of oxygen gas, the alcohol with methanol or ethanol. This reaction occurs in the presence of a catalyst comprising palladium and a co-catalyst comprising bismuth, tellurium, lead, cerium, titanium, zinc and/or niobium (most preferably at least bismuth and tellurium). Alternatively that catalyst can be used to generate an acid from that alcohol, when water is also added to the reaction mix.
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- 3-SUBSTITUTED PYRAZOLES AND USE AS DLK INHIBITORS
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The present invention provides for compounds of Formula (I) and various embodiments thereof, and compositions comprising compounds of Formula (I) and various embodiments thereof. (I) In compounds of Formula I, the groups R1, R2, R3, R4, R5, R6 and R7 have the meaning as described herein. The present invention also provides for methods of using compounds of Formula I and compositions comprising compounds of Formula (I) as DLK inhibitors and for treating neurodegeneration diseases and disorders.
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Page/Page column 172; 173
(2014/08/06)
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- Aerobic oxidation of diverse primary alcohols to methyl esters with a readily accessible heterogeneous Pd/Bi/Te catalyst
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Efficient aerobic oxidative methyl esterification of primary alcohols has been achieved with a heterogeneous catalyst consisting of 1 mol % Pd/charcoal (5 wt %) in combination with bismuth(III) nitrate and tellurium metal. The Bi and Te additives significantly increase the reaction rate, selectivity, and overall product yields. This readily accessible catalyst system exhibits a broad substrate scope and is effective with both activated (benzylic) and unactivated (aliphatic) alcohols bearing diverse functional groups.
- Powell, Adam B.,Stahl, Shannon S.
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supporting information
p. 5072 - 5075
(2013/10/22)
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- Asymmetric cross-dimerization between methyl methacrylate and substituted alkene by Ru(0)-bicyclononadiene complex
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New Ru(0)-naphthalene complexes containing a bicyclononadiene ligand catalyze the linear cross-dimerization between methyl methacrylate and substituted alkenes by an oxidative coupling mechanism. The chiral (S,S)-2-methylbicyclo[3.3.1]nona-2,6-diene complex (S,S)-1b catalyzes asymmetric linear cross-dimerization between methyl methacrylate and 2,5-dihydrofuran to give the cross-dimer in 74% yield in 80% ee.
- Hiroi, Yuki,Komine, Nobuyuki,Komiya, Sanshiro,Hirano, Masafumi
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supporting information
p. 2486 - 2489
(2013/07/05)
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- Compounds Which Selectively Modulate The CB2 Receptor
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Compounds of formula (I) are disclosed. Compounds according to the invention bind to and are agonists, antagonists or inverse agonists of the CB2 receptor, and are useful for treating inflammation. Those compounds which are agonists are additionally usefu
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Page/Page column 56
(2010/04/23)
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- Highly efficient rhodium catalysts for the asymmetric hydroformylation of vinyl and allyl ethers using C1-symmetrical diphosphite ligands
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Here, we describe the successful application of novel glucofuranose-derived 1,3-diphosphites in the rhodium-catalysed asymmetric hydroformylation of vinyl acetate, 2,5-dihydrofuran and 2,3-dihydrofuran. In the hydroformylation of vinyl acetate, total regioselectivity and high ee (up to 73%) were obtained. When 2,3- and 2,5-dihydrofuran were the substrates, total chemo- and regioselectivities were achieved together with ees up to 88%. These results correspond to the highest ee values reported to date in the asymmetric hydroformylation of these substrates. The HP-NMR studies of the [RhH(CO) 2(L)] species (L=15 and 17) demonstrated that both ligands coordinate to the Rh centre in an eq-eq fashion. The complex [RhH(CO)2(15)] was detected as a single isomer with characteristic features of eq-eq coordination. However, the broadening of the corresponding signals indicated that this species is rapidly interchanging in solution. In contrast, complex [RhH(CO) 2(17)] was detected as a mixture of two conformational isomers at low temperature due to the greater flexibility of the monocyclic backbone of this ligand.
- Gual, Aitor,Godard, Cyril,Castillon, Sergio,Claver, Carmen
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experimental part
p. 463 - 477
(2010/06/13)
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- Asymmetric Hydroformylation of Heterocyclic Olefins Catalyzed by Chiral Phosphine-Phosphite-Rh(I) Complexes
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Asymmetric hydroformylation of heterocyclic olefins catalyzed by phosphine-phosphite-Rh(I) complexes has been investigated. Hydroformylation of symmetrical heterocyclic olefins such as 2,5-dihydrofuran, 3-pyrroline derivatives, and 4,7-dihydro-1,3-dioxepin derivatives afforded the optically active aldehydes as single products in 64-76% ee. Unsymmetrical substrates such as 2,3-dihydrofuran and N-(tert-butoxycarbonyl)-2-pyrroline gave a mixture of regioisomers. From N-(tert-butoxycarbonyl)-2-pyrroline was obtained N-(tert-butoxycarbonyl)pyrrolidine-2-carbaldehyde in 97% ee. The hydroformylation products from 2,5-dihydrofuran and N-(tert-butoxycarbonyl)-3-pyrroline have the opposite configurations to those from 2,3-dihydrofuran and N-(tert-butoxycarbonyl)-2-pyrroline, respectively, with the same catalyst. The new phosphine-phosphite ligand (R,S)-3,3′-Me2-BINAPHOS [= (A)-2-(diphenylphosphino)-1,1′-binaphthalen-2′-yl (S)-3,3′-dimethyl-1,1′-binaphthalene-2,2′-diyl phosphite] was prepared and its hydridorhodium complex was characterized by NMR spectroscopy. Using (R,S)-3,3′-Me2-BINAPHOS as a ligand, the enantioselectivity was improved for some substrates. In addition, higher catalytic activity was observed with this ligand for most of the substrates employed.
- Horiuchi, Toshihide,Ohta, Tetsuo,Shirakawa, Eiji,Nozaki, Kyoko,Takaya, Hidemasa
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p. 4285 - 4292
(2007/10/03)
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