- (CAMPHORYLSULFONYL)IMINE DIANION IN THE SYNTHESIS OF NEW OPTICALLY PURE (CAMPHORYLSULFONYL)OXAZIRIDINE DERIVATIVES
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New, more efficient enantiomerically pure (camphorylsulfonyl)oxaziridines are prepared by mono alkylation of the dianion of (camphorylsulfonyl)imine at the carbon atom adjacent to the sulfonyl group.
- Davis, Franklin A.,Weismiller, Michael C.,Lal, G. Sankar,Chen, Bang Chi,Przeslawski, Robert M.
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Read Online
- Application in asymmetric Morita-Baylis-Hillman reactions
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N-Substituted 2-exo-hydroxybornyl-10-sulfonamides, prepared as potential chiral auxiliaries for use in asymmetric Morita-Baylis-Hillman (MBH) reactions, have been treated with acryloyl chloride to afford the corresponding 2-exo-Acrylate esters as MBH subs
- McIteka, Lulama P.,Lobb, Kevin A.,Kaye, Perry T.
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p. 151 - 163
(2016/10/22)
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- A PROCESS FOR THE MANUFACTURE OF CHIRAL CATALYSTS AND THEIR SALTS
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The present invention provides efficient and economical methods for synthesis of (-)-2-exo-morpholinoisoborne-10-thiol, its enantiomer, and related chiral catalysts. Novel compounds and methods of asymmetric synthesis are also disclosed.
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Paragraph 0105; 0106
(2013/06/27)
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- Synthesis, structure and activity of sulfonamides derived from (+)-camphor in the enantioselective addition of diethylzinc to benzaldehyde
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New chiral sulfonamides derived from (+)-camphor, with different substituents on camphor C2 and sulfonamide N, were synthesized. Their activity was tested in the reaction of Et2Zn addition to benzaldehyde. The yield of the reaction was 44-96%, the enantiomeric excess was 1-69%. Sulfonamides possessing the 2-hydroxyl group gave an excess of 1-(S)-phenylpropanol, while catalysts containing other sulfonamides gave 1-(R)-phenylpropanol as a major product. The best catalytic efficacy was observed for sulfonamides with (R)-C2-OH group, while the use of thioketo- and mercaptosulfonamides resulted in low enantiomeric excess and yields not exceeding 60%. Crystal structures have been determined for sulfonamides with N-benzyl moiety and different substituents on the C2 atom. The structural analysis revealed the presence of intramolecular N?O(C2) and Osulfo?O(C2) H-bonds, what confirms the ability of these molecules to adopt the conformation required for their bidentate coordination to Ti(IV) via the sulfonamide group and substituent at C2. The coordination mode for investigated sulfonamides was determined with the IR spectra for five obtained Ti(IV) complexes and crystal structure analysis of the ligands. The 3D structures of Ti(IV) complex catalysts containing investigated sulfonamides were postulated, which are consistent with the reported chirality of the addition product and observed % ee.
- Kozakiewicz, Anna,Ullrich, Ma?gorzata,We?niak, Miros?aw,Wojtczak, Andrzej
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experimental part
p. 128 - 140
(2010/10/01)
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- Synthesis of camphorsulfonamide-based quinoline ligands and their N-oxides: first use in the enantioselective addition of organozinc reagents to aldehydes
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The preparation of several camphorsulfonamide-based quinoline derivatives and their N-oxides was accomplished via an indirect Friedlaender synthesis using aminobenzylic alcohols and RuCl2(DMSO)4 as a catalyst. These ligands were tested in the enantioselective addition of dialkylzinc reagents to aldehydes, with enantiomeric excesses up to 96%. A similar protocol using triphenylborane and diethylzinc gave the corresponding phenylation process.
- Martinez, Ricardo,Zoli, Luca,Cozzi, Pier Giorgio,Ramon, Diego J.,Yus, Miguel
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experimental part
p. 2600 - 2607
(2009/04/11)
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- Synthesis of novel chiral Schiff bases and their application in asymmetric transfer hydrogenation of prochiral ketones
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Novel chiral Schiff bases were synthesized from (+)-camphor, and their application to asymmetric transfer hydrogenation of prochiral ketones is described. The asymmetric transfer hydrogenation reaction could afford excellent conversion rates (up to 97.3%) and up to 27.3% enantiomeric excess.
- Zhou, Zhongqiang,Bian, Yongjun
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experimental part
p. 682 - 687
(2010/11/04)
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- Camphordisulfonamides: Good chiral ligands for the addition of dialkylzinc to aliphatic aldehydes
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The preparation of several disulfonamides derived from camphor and their use in the titanium tetraisopropoxide-promoted enantioselective addition of dialkylzinc to aldehydes is described. The enantiomeric ratio is up to 98:2, the best results being obtained for aliphatic aldehydes. Copyright (C) 2000 Elsevier Science Ltd.
- Prieto, Oscar,Ramon, Diego J.,Yus, Miguel
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p. 1629 - 1644
(2007/10/03)
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- Camphorsulfonamide derivatives: A new class of chiral catalysts for the titanium alkoxide-promoted addition of dialkylzinc to aldehydes
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The enantioselective addition of dialkylzinc to several aldehydes, using different chiral bidentate ligands (3a-j, 4a-h) [derived from (+)-10-camphorsulfonyl chloride] and titanium alkoxide as catalysts, is studied. The influence of temperature, titanium alkoxide, stoichiometry, additive, aldehyde and ligand structure is also studied.
- Ramoen, Diego J.,Yus, Miguel
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p. 2479 - 2496
(2007/10/03)
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