- Synthesis of N-tetrasubstituted cyclam derivatives appended with sulfonyl or sulfinyl groups via aza-Michael addition
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Azamacrocycles bearing four arylsulfonyl or arylsulfinyl pendant arms have been synthesised with good yields through nucleophilic addition of 1,4,8,11-tetraazacyclotetradecane (cyclam) to phenylvinylsulfone, phenylvinylsulfoxide or (R)-tolylvinylsulfoxide
- de Castries, Augustin,Escande, Aude,Fensterbank, Hélène,Magnier, Emmanuel,Marrot, Jér?me,Larpent, Chantal
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- Hydrogenative Kinetic Resolution of Vinyl Sulfoxides
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Enantiopure sulfoxides are valuable precursors of organosulfur compounds with broad application in organic and pharmaceutical chemistry. An unprecedented strategy for obtaining highly enantioenriched sulfoxides based on a hydrogenative kinetic resolution using Rh-complexes of phosphine-phosphite ligands as catalysts is reported. After optimization, highly efficient conditions for the kinetic resolution of racemic sulfoxides have been identified. This methodology has been applied to a set of racemic aralkyl or aryl vinyl sulfoxides and allowed the isolation of both recovered and reduced products in excellent yields and enantioselectivities (up to 99% and 97% ee, respectively; 16 examples).
- Lao, Joan R.,Fernndez-Prez, Hctor,Vidal-Ferran, Anton
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p. 4114 - 4117
(2015/09/01)
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- Highly stereoselective asymmetric pummerer reactions that incorporate intermolecular and intramolecular nonbonded S...O interactions
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New chiral sulfoxides (RS,S)-3, (SS,S)-3, (R S,S)-4, and (SS,S)-4 and known chiral sulfoxides (R S)-5, (RS)-6, and (RS)-7 were synthesized, and the stereochemistry of the new sulfoxides (RS,S)-3 and (R S,S)-4 was determined by X-ray crystallographic analysis. In their crystallographic structures, the intramolecular nonbonded S...O close contacts were recognized. Analyses of several sulfoxide complexes including rac-11 with N,N-dimethylacetamide (DMAC) or N-methyl-2-pyrrolidone (NMP) in a MeOH solution utilizing cold-spray ionization mass spectrometry provided, for the first time, direct information for intermolecular nonbonded S...O interactions between sulfoxides and amide (or lactam) in a solution. Highly diastereoselective and enantioselective Pummerer reactions based on the concept of intermolecular and intramolecular nonbonded S...O interactions were performed by treatment of several chiral sulfoxides (RS, S)-3, (SS, S)-3, (RS, S)-4, (SS, S)-4, (R S)-5, (RS)-6, and (RS)-7 with acetic anhydride and trimethylsilyl triflate (TMSOTf) in DMAC, NMP, N,N-dimethylformamide, and N-formylpiperidine. Mechanistic studies on these facile stereoselective Pummerer reactions revealed the necessity for the amide/TMSOTf complex, such as 26 or 27, to be an efficient activation reagent for Ac2O and a trapping reagent for the released acetate ion, and that DMAC and NMP had a positive effect on this highly stereoselective chiral transfer reaction.
- Nagao, Yoshimitsu,Miyamoto, Satoshi,Miyamoto, Motoyuki,Takeshige, Hiroe,Hayashi, Kazuhiko,Sano, Shigeki,Shiro, Motoo,Yamaguchi, Kentaro,Sei, Yoshihisa
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p. 9722 - 9729
(2007/10/03)
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- Probing the formation of bicyclo[4.2.0]octan-1-ols
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Reaction of lithium enolates of simple ketones with (±)-phenyl vinyl sulfoxide has potential for the convergent construction of complex fused ring systems containing a bicyclo[n.2.0]alkan-1-ol. The formation of sulfinylbicyclo[4.2.0]octan-1-ols 1-3 from the lithium enolate of cyclohexanone with (±)-phenyl vinyl sulfoxide or (R)-(+)-p-tolyl vinyl sulfoxide 18 was used to probe the mode of this novel cyclization reaction. Using phenyl vinyl sulfoxide, variations in the reaction lighting and solvent were investigated, in conjunction with radical trapping (TEMPO) and isotope labeling (deuterium) experiments. Cyclization to form sulfinylbicyclooctanols 1-3 is likely to proceed via an intermediate that ring closes to the bicycloalkanol anion 11 and was presently favored by the use of solvents such as THF or DME.
- Loughlin, Wendy A.,Rowen, Catherine C.,Healy, Peter C.
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p. 5690 - 5698
(2007/10/03)
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- An efficient resolution of (±)-p-tolylvinylsulfoxide using (-)-menthol
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The preparation of enantiopure (+)-(R)(S) and (-)-(S)(S)-p- tolylvinylsulfoxide using (-)-menthol as a resolving agent is described.
- Alexandre, Christian,Guillot, Chantal,Hayes, Patricia,Maignan, Christian
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p. 5769 - 5770
(2007/10/03)
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- Stereoselective synthesis of racemic and optically active E-vinyl and E- dienyl sulfoxides via Wittig reaction of α-sulfinyl phosphonium ylides
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A series of α-sulfinyl phosphonium ylides have been obtained in the reaction of phosphonium mono- and diylides with sulfinic acid esters. The use of (-)-(S)-menthyl p-toluenesulfinate in this reaction afforded the corresponding (S)-((p-tolylsulfinyl)methyl)triphenylphosphonium ylide. The Wittig reaction of these ylides with saturated and unsaturated aldehydes resulted in the formation of racemic and optically active (+)-(R)-vinyl and dienyl sulfoxides with the E-geometry. The synthesis of (+)-(R)-((p- tolylsulfinyl)methyl)triphenylphosphonium iodide as a precursor of the optically active ylide has also been described.
- Mikolajczyk, Marian,Perlikowska, Wieslawa,Omelanczuk, Jan,Cristau, Henri-Jean,Perraud-Darcy, Anne
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p. 9716 - 9722
(2007/10/03)
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- Asymmetric synthesis of chiral sulfoxides and sulfinimines by using N-sulfinylsultam
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Bornane-10,2-sultam 1 is stereoselectively converted by DMAP-assisted sulfinylation to diastereomerically pure (2R)-N-[(R)-p-tolylsulfinyl]-bornane-10,2-sultam 2 in 77% yield. The crystalline sulfinylating agent 2 reacts with a variety of nucleophiles to afford sulfoxides 3 and sulfinimines 5 in excellent yields and enantioselectivities.
- Oppolzer, Wolfgang,Froelich, Olivier,Wiaux-Zamar, Chantal,Bernardinelli, Gerald
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p. 2825 - 2828
(2007/10/03)
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- Highly Enantioselective Synthesis of a Corey Prostaglandin Intermediate
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(R)-p-tolyl vinyl sulfoxide 8 was transformed into the corresponding ethoxysulfonium compound 9 which smoothly underwent reaction with 5-benzyloxymethyl-1,3-cyclopentadiene 2 to give, after basic treatment, the bicyclic sulfoxide 10 with very high de.This
- Ronan, Baptiste,Kagan, Henri B.
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p. 115 - 122
(2007/10/02)
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- Simple and Stereocontrolled Preparation of Optically Pure (E)- and (Z)-1-Alkenyl p-Tolyl Sulfoxides via 1-Alkynyl p-Tolyl Sulfoxides
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1-Alkynylmagnesium bromides react cleanly and stereospecifically with (-)-menthyl (-)-(S)-p-toluenesulfinate (2) in toluene to produce chiral 1-alkynyl p-tolyl (+)-(S)-sulfoxides 5a-d in high yields.Reduction of 5a-d with lithium aluminum hydride in THF a
- Kosugi, Hiroshi,Kitaoka, Masaki,Tagami, Katsuya,Takahashi, Akira,Uda, Hisashi
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p. 1078 - 1082
(2007/10/02)
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- Asymmetric Induction in the Michael Reaction by Means of Chiral Phase-transfer Catalysts derived from Cinchona and Ephedra Alkaloids
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Asymmetric induction in the Michael reaction has been achieved using alkaloidonium salts in a two-phase system with optical yields of up to 36 and 26percent in the addition to αβ-unsaturated ketones of thiols and nitroalkanes respectively.The presence of a hydroxy-group β to the 'onium function is essential to achieve substantial asymmetric syntheses.
- Colonna, Stefano,Re, Alberto,Wynberg, Hans
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p. 547 - 552
(2007/10/02)
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