- Photoredox/Nickel Dual Catalysis for the C(sp3)–C(sp3) Cross-Coupling of Alkylsilicates with Alkyl Halides
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Alkylsilicates were engaged under photoredox/nickel dual catalysis conditions with alkyl halides for the first time. The C(sp3)–C(sp3) cross-coupling products were obtained in moderate yields and were accompanied by the homocoupling
- Lévêque, Christophe,Corcé, Vincent,Chenneberg, Ludwig,Ollivier, Cyril,Fensterbank, Louis
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supporting information
p. 2118 - 2121
(2017/04/24)
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- A lewis acid-promoted pinner reaction
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Carbonitriles and alcohols react in a Lewis acid-promoted Pinner reaction to carboxylic esters. Best results are obtained with two equivalents of trimethylsilyl triflate as Lewis acid. Good yields are achieved with primary alcohols and aliphatic or benzylic carbonitriles, but the straightforward synthesis of acrylates and benzoates starting with acrylonitrile and benzonitrile, respectively, is similarly possible. Phenols are not acylated under these reaction conditions. The method has been used for the first total synthesis of the natural product monaspilosin. In the reaction of benzyl alcohols variable amounts of amides are formed in a Ritter-type side reaction.
- Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
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supporting information
p. 1572 - 1577
(2013/10/22)
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- A hydrogen chloride-free pinner reaction promoted by lewis acids
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A hydrogen chloride-free variation of the Pinner reaction was developed, in which alcohols react with carbonitriles to furnish carboxylates. Best results were achieved with aliphatic alcohols, and aliphatic or benzylic nitriles in the presence of 2 equiv. of trimethylsilyl triflate (Me3SiOTf). With these substrates, yields exceeding 80% were achieved. A strictly neutral variation of this protocol is possible, when 1 equiv. of Et3N is added to the reaction mixture. Copyright
- Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
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p. 1851 - 1856,6
(2012/12/12)
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- Synthesis of analogues of Acyclic nucleoside diphosphates containing a (phosphonomethyl)phosphanyl moiety and studies of their phosphorylation
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Acyclic nucleoside diphosphonate derivatives of purines and pyrimidines were prepared by Mitsunobu reaction of suitably protected heterocyclic bases with alcohols containing the (phosphonomethyl)phosphanyl moiety. Furthermore, nonhydrolyzable acyclic analogues of dUDP were prepared as potential inhibitors of dUTPase. Their phosphorylation to analogues of dUTP, however, gave mixtures of linear and branched phosphates. The courses of the phosphorylation reactions were followed by 31P NMR spectroscopy, and we discovered that both phosphonate and phosphinate moieties react with 1,1'-carbonyldiimidazole and tri-n-butylammonium phosphate. The pKa values of the (phosphonomethyl)phosphanyl system were also determined by 31P NMR spectroscopy ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009).
- Dolakova, Petra,Dracinsky, Martin,Fanfrlik, Jindrich,Holy, Antonin
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experimental part
p. 1082 - 1092
(2009/07/19)
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- MECHANISMS OF FREE-RADICAL REACTIONS. XXIV. QUANTITATIVE DESCRIPTION OF THE POLAR EFFECTS OF SUBSTITUENTS ON THE KINETICS OF THE FREE-RADICAL CHLORINATION OF ALIPHATIC COMPOUNDS BY N-CHLOROPIPERIDINE
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The free-radical chlorination of 1-substituted alkanes with electron-withdrawing substituents by N-chloropiperidine in trifluoroacetic acid was studied by the method of competing reactions, and the relative rate constants were obtained for all positions of the substrates.The data on the position selectivity can be described satisfactorily by means of an electrostatic model of the polar effect of the substituent, calculated according to the Kirkwood-Westheimer equation.The obtained characteristics of the electrostatic effect can be successfully applied to calculation of the substrate selectivity and the intermolecular relative rate constants for all the positions, beginning with the third.The Taft equation is unsuitable for description of the effect of substituents on the reaction rate.
- Dneprovskii, A. S.,Mil'tsov, S. A.,Arbuzov, P. V.
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p. 1826 - 1835
(2007/10/02)
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- Experimental evidence for AcO-7 neighboring group participation
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The reaction of diol diacetates with anhydrous aluminium chloride at ca 100° leads to displacement of only one of the acetoxy groups by chlorine. An oxygen-18 label study has shown that these displacements take place via acetoxonium intermediates and has provided direct evidence for the intervention of a seven-membered ring acetoxonium ion in the displacement of acetate by chlorine in 1,4-butanediol diacetate.
- Wilen, Samuel H.,Delguzzo, Luciano,Saferstein, Richard
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p. 5089 - 5094
(2007/10/02)
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- Novel omega-(N-imidazolyl)alkyl ethers of 1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2-ones
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Novel compound wherein n is an integer of 1 to 8; R1 is hydrogen or alkyl of 1-6 carbons; R2 is hydrogen; R3 is hydrogen, alkyl of 1-6 carbons, phenyl, benzyl, hydroxy lower alkyl, carbamoyl alkyl, carboxyalkyl, alkoxycarbonylalkyl; R4 is hydrogen, alkyl of 1-6 carbons, benzyl, or hydroxy lower alkyl; Y is hydrogen, alkyl of 1 to 4 carbon atoms, halo or lower alkoxy; any of its optical isomers, the mixture thereof, or the pharmaceutically acceptable acid addition salt. These compounds are inhibitors of thromboxane synthetase and cyclic AMP phosphodiesterase and are therefore potential cardiovascular agents particularly useful as platelet aggregation inhibitors and anti-thrombotic agents. Accordingly, these compounds will preferably be useful in treating cardiovascular disorders with thrombotic complications. However, they also possess vasodilatory, antisecretory, antihypertensive, inotropic and antimetastatic activities.
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- Synthesis of Nitriles from Haloesters, Haloketones and Haloethers
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The action of NaCN on haloesters, haloketones and haloethers has been studied.Haloesters wherein halogen and ester functions are located on adjacent carbon atoms, do not furnish the corresponding nitriles, whereas those with halogen and ester functions not located on adjacent carbon atoms, furnish the corresponding nitriles in good yields.The presence of hydroxy or ether function on the carbon adjacent to primary halide bearing carbon atom does not interfere in the reaction with cyanide. δ-Haloketones are transformed to ketonitriles, γ-Haloketones are transformed to cyclopropyl ketones and epoxyhalides to epoxynitriles.
- Talekar, D. G.,Joshi, P. L.,Ramaiah, P.,Rao, A. S.
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p. 145 - 151
(2007/10/02)
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- SYNTHESIS OF(E) AND (Z) ALKENES VIA PALLADIUM OR NICKEL-CATALYZED REACTION OF VINYL CHLORIDES WITH GRIGNARD REAGENTS.
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We herein described (i) a useful transformation of (E) and (Z) vinyl chlorides into E (and Z) olefins and (ii) an efficient preparation of monoenic alcohols or acetates and its application to insect pheromones.
- Ratovelomanana, Victorin,Linstrumelle, Gerard
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p. 179 - 188
(2007/10/02)
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- Chlorination of Carboxylic Acid Derivatives. IX. Liquid Phase Chlorination of Aliphatic C2-C8 Alkyl Acetates. EI Mass Spectra of Monochlorinated Esters
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A series of aliphatic alkyl acetates from ethyl to octyl acetate was chlorinated in the liquid phase in order to obtain monochlorinated products.The chlorination of esters was carried out with chlorine in the liquid phase in the absence and in the presence of benzene and with sulfuryl chloride in the presence of Bz2O2.The products were determined by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry.Chlorination is appreciably deactivated at the 1-position, particularly with SO2Cl2, the deactivation at the 2-position being strongest with Cl2 in the presence of benzene.The amounts of 1-chloro and ω-chloro isomers constituted the greatest disparity between the chlorination methods.The most characteristic mass spectral fragment ions of the 35 chlorinated alkyl acetates are given.
- Korhonen, Ilpo O. O.
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