- Efficient preparation of α,α-dialkyl-α-(phenylselanyl) acetates and α,β-unsaturated esters from the corresponding α,α-dialkyl-α-cyanoacetates by a lithium naphthalenide induced reductive selenenylation process
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An array of α,α-dialkyl-α-(phenylselanyl)acetates has been synthesized very efficiently from readily available α,α- dialkyl-α-cyanoacetates, by use of lithium naphthalenide induced reductive α-selenenylation as a key operation. Moreover, the selanyl esters thus generated in situ could be converted further, in a one-pot treatment with hydrogen peroxide and acetic acid, into the corresponding α,β- unsaturated esters in moderate to high yields. The C=C bond formation was highly regio- and/or diastereoselective in some cases. Georg Thieme Verlag Stuttgart.
- Ko, Yen-Chun,Zhu, Jia-Liang
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p. 3659 - 3665
(2008/09/19)
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- One-pot asymmetric conjugate addition-trapping of zinc enolates by activated electrophiles
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The copper-catalyzed asymmetric conjugate addition of dialkyl zinc leads to homochiral zinc enolates. These intermediates were trapped in situ with activated allylic electrophiles, without the need of additional palladium catalysis. High trans selectivity
- Rathgeb, Xavier,March, Sebastien,Alexakis, Alexandre
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p. 5737 - 5742
(2007/10/03)
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- 3-aryl-2-isoxazolines as antiinflammatory agents
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This invention relates to 3-aryl-2-isoxazoline compounds which are selective inhibitors of phosphodiesterase type IV (PDEIV). The 3-aryl-2-isoxazolines are useful in the treatment of AIDS, asthma, arthritis, bronchitis, chronic obstructive pulm
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- Preparation et etude de nouveaux derives organozinciques allyliques fonctionnels
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Stable organozinc compounds derived from alkyl-3-alkyl-2-(bromomethyl)-propenoates have been prepared.NMR 13C, 1H and IR studies show only one Z stereoisomer (no methylenic form) with a strong chelation between zinc and the carbonyl oxygen of the ester and solvated by only one solvent molecule.Hydrolysis can be achieved by two concurrent mechanisms with or without transposition.
- Lambert, Francois,Kirschleger, Bernard,Villieras, Jean
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p. 273 - 286
(2007/10/02)
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- Preparation des organozinciques derives de l'α-bromomethyl acrylate d'ethyle et de ses homologues
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The preparation of the bromozinc derivatives of various α-bromoalkyl acrylates (aliphatic and alicyclic) results in high yields when carried out on 30 mesh activated granular zinc, between 14 and 20 deg C in ethereal solvents (THF, DME, ether).Under these conditions duplication can be minimized (5-15 percent) especially with t-butyl acrylates.These α-functional allylic orgazinc derivatives have been characterized by hydrolysis and coupling with benzaldehyde.
- Alami, Najat El,Belaud, Chantal,Villieras, Jean
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- Hydrogenolysis of Small Cycloalkanes, XI. - Hydrogenation of Bicyclobutane-1- and -2-carboxylates
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Hydrogenation of ethyl bicyclobutane-2-carboxylate (1) with Pd/C in ethanol at normal conditions leads to 95 percent of ethyl 2-methylbutyrate (2) and 5 percent of ethyl n-valerate (3).The corresponding 1-carboxylic acid ester 8 yields 99 percent of 2 but less than 1 percent of cyclobutane as well as the cis- and trans-2-methylcyclopropanecarboxylates 5 and 9.In this case 2-methylenebutyric and cis- and trans-2-methylcrotonic acid esters (10, 11a, and 12) can be detected as intermediates.From these, conclusions can be made about the mechanism at the catalyst. 5 is the main product with a poisoned catalyst.
- Hertzsch, Winfried,Musso, Hans
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p. 1485 - 1491
(2007/10/02)
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