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Prochiral Ketones (prochiral + ketone)
Selected AbstractsSynthesis and Evaluation of a Broad Range of New Chiral (Aminoalkyl)phosphane Ligands for Asymmetric Hydrogen-Transfer Reduction of Prochiral KetonesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2003Matthieu Léautey Abstract Twenty new chiral (aminoalkyl)phosphane ligands have been prepared from four enantiomerically pure advanced chiral compounds. We describe their use for asymmetric hydrogen-transfer reduction of three prochiral ketones. Enantioselectivities up to 90% were obtained. We investigated the influence on the enantioselectivity of each part of these new (aminoalkyl)phosphane ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] ChemInform Abstract: Mild and Practical Reductions of Prochiral Ketones to Chiral Alcohols Using the Chiral Boronic Ester TarB,H.CHEMINFORM, Issue 15 2009Scott Eagon Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis of Novel Chiral Schiff Bases and Their Application in Asymmetric Transfer Hydrogenation of Prochiral Ketones.CHEMINFORM, Issue 10 2009Zhongqiang Zhou Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Catalytic Asymmetric Borane Reduction of Prochiral Ketones by Using (S)-2-(Anilinomethyl)pyrrolidine.CHEMINFORM, Issue 25 2008Naoya Hosoda Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] (5S)-1,3-Diaza-2-imino-3-phenylbicyclo[3.3.0]octane: First Example of Guanidine Based in situ Recyclable Chiral Catalytic Source for Borane-Mediated Asymmetric Reduction of Prochiral Ketones.CHEMINFORM, Issue 43 2006Deevi Basavaiah Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] (2S)-2-Anilinomethylpyrrolidine: An Efficient in situ Recyclable Chiral Catalytic Source for the Borane-Mediated Asymmetric Reduction of Prochiral Ketones (I) in Refluxing Toluene.CHEMINFORM, Issue 43 2006Deevi Basavaiah Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Toward Effective Chiral Catalysts Containing the N,P=O Structural Framework for the Borane-Mediated Asymmetric Reduction of Prochiral Ketones.CHEMINFORM, Issue 43 2004Deevi Basavaiah Abstract For Abstract see ChemInform Abstract in Full Text. [source] Use of Diamines Containing the ,-Phenylethyl Group as Chiral Ligands in the Asymmetric Hydrosilylation of Prochiral Ketones.CHEMINFORM, Issue 23 2004Virginia M. Mastranzo Abstract For Abstract see ChemInform Abstract in Full Text. [source] Enantiospecific Synthesis of Pyridinylmethyl Pyrrolidinemethanols and Catalytic Asymmetric Borane Reduction of Prochiral Ketones.CHEMINFORM, Issue 22 2004Yong-Xin Zhang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Asymmetric Oxazaborolidine-Catalyzed Reduction of Prochiral Ketones with N-tert-Butyl-N-trimethylsilylamine,borane.CHEMINFORM, Issue 36 2003Ramon E. Huertas Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Catalytic Asymmetric Borane Reduction of Prochiral Ketones by the Use of Diazaborolidine Catalysts Prepared from Chiral ,-Diamines.CHEMINFORM, Issue 14 2001Shinsuke Sato Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Comparative Study of Cyanobacteria as Biocatalysts for the Asymmetric Synthesis of Chiral Building BlocksENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2006J. Havel Abstract The three representative cyanobacteria, Synechococcus PCC7942, Anabaena variabilis, and Nostoc muscorum, were studied for their ability to asymmetrically reduce the prochiral ketones 2,-3,-4,-5,-6,-pentafluoroacetophenone, ethyl 4-chloroacetate, 4-chloroacetophenone, and ethylbenzoylacetate to the corresponding chiral alcohols. Photosynthesis as well as respiration was applied for intracellular regeneration of the NAD(P)H cofactor. It was shown for the first time that all cyanobacteria were able to reduce the prochiral ketones asymmetrically without light for cofactor regeneration. By comparison of the cell specific product formation capacities of cyanobacteria with typical heterotrophic whole cell biocatalysts in batch processes, it is shown that comparable or, in some cases, better performances at high enantiomeric excess (ee > 99.8,%) are obtained. As a consequence of a generally strong product inhibition, in situ product removal must be applied in order to restore process efficiency when using cyanobacteria as biocatalysts. [source] Synthesis and Evaluation of a Broad Range of New Chiral (Aminoalkyl)phosphane Ligands for Asymmetric Hydrogen-Transfer Reduction of Prochiral KetonesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2003Matthieu Léautey Abstract Twenty new chiral (aminoalkyl)phosphane ligands have been prepared from four enantiomerically pure advanced chiral compounds. We describe their use for asymmetric hydrogen-transfer reduction of three prochiral ketones. Enantioselectivities up to 90% were obtained. We investigated the influence on the enantioselectivity of each part of these new (aminoalkyl)phosphane ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Hexahydropyrrolo[2,3- b]indoles: A New Class of Structurally Rigid Tricyclic Skeleton for Oxazaborolidine-Catalyzed Asymmetric Borane ReductionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Jian Xiao Abstract A new class of structurally rigid tricyclic chiral ligands based on the hexahydropyrrolo[2,3- b]indole skeleton has been rationally designed and the catalytic abilities in asymmetric catalysis have been shown in the enantioselective borane reduction of prochiral ketones to afford the chiral alcohols in excellent yields and high enantioselectivities (up to 97% ee). [source] Chiral iridium(I) bis(NHC) complexes as catalysts for asymmetric transfer hydrogenationAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 7 2010Claus Diez Abstract The common use of NHC complexes in transition-metal mediated C,C coupling and metathesis reactions in recent decades has established N -heterocyclic carbenes as a new class of ligand for catalysis. The field of asymmetric catalysis with complexes bearing NHC-containing chiral ligands is dominated by mixed carbene/oxazoline or carbene/phosphane chelating ligands. In contrast, applications of complexes with chiral, chelating bis(NHC) ligands are rare. In the present work new chiral iridium(I) bis(NHC) complexes and their application in the asymmetric transfer hydrogenation of ketones are described. A series of chiral bis(azolium) salts have been prepared following a synthetic pathway, starting from L -valinol and the modular buildup allows the structural variation of the ligand precursors. The iridium complexes were formed via a one-pot transmetallation procedure. The prepared complexes were applied as catalysts in the asymmetric transfer hydrogenation of various prochiral ketones, affording the corresponding chiral alcohols in high yields and moderate to good enantioselectivities of up to 68%. The enantioselectivities of the catalysts were strongly affected by the various, terminal N -substituents of the chelating bis(NHC) ligands. The results presented in this work indicate the potential of bis-carbenes as stereodirecting ligands for asymmetric catalysis and are offering a base for further developments. Copyright © 2010 John Wiley & Sons, Ltd. [source] Asymmetric transfer hydrogenation catalyzed by a novel planar chiral N -heterocyclic carbene,rhodium(I) complexAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2009Ru Jiang Abstract A novel chelated ferrocene-based planar chiral N-heterocyclic carbene-Rh(I) complex was synthesized by a simple method. It was applied to the asymmetric transfer hydrogenation of prochiral ketones. Enantioselectivities of up to 67% ee were observed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Chemo- and Stereoselective Iron-Catalyzed Hydrosilylation of KetonesCHEMISTRY - AN ASIAN JOURNAL, Issue 7 2010Daniele Addis Abstract The reduction of ketones with polymethylhydrosiloxane (PMHS) gives the corresponding alcohols in good to excellent yield applying iron-based catalyst systems. In the case of prochiral ketones, the use of Fe(OAc)2/(S,S)-Me-DuPhos leads to high enantioselectivity up to 99,%,ee. The reaction proceeds in the presence of several functional groups such as esters, halides as well as conjugated double bonds, with high chemoselectivity. The advantage of this protocol is that the reaction requires no activating agents or additives. [source] Chiral amino amides for the ruthenium(II)-catalyzed asymmetric transfer hydrogenation reaction of ketones in waterCHIRALITY, Issue 1 2010Jincheng Mao Abstract The chiral amino amide 3 was derived from L -proline and used for the [RuCl2(p -cymene)]2 -catalyzed asymmetric transfer hydrogenation of prochiral ketones performed in water. Moderate to good chemical selectivities (up to 95% yield) and enantioselectivities (up to 90% ee) were obtained in the presence of 2 mol % of TBAB (n -Bu4NBr) as the phase transfer catalyst. Chirality, 2010. © 2009 Wiley-Liss, Inc. [source] Preparation of highly optically pure homochiral sulfide-containing alcohols via oxazaborolidine-catalyzed asymmetric borane reduction of ketonesCHIRALITY, Issue 6 2004Jiaxi Xu Abstract Highly optically pure homochiral 1-(4-alkylthiophenyl) alcohols were prepared efficiently and practically via the oxazaborolidine-catalyzed asymmetric borane reduction of prochiral ketones in toluene at 25°C. The coordination of the sulfur atom in the ketones to the boron atom in the catalyst and borane can be inhibited under these reduction conditions. Chirality 16:341,346, 2004. © 2004 Wiley-Liss, Inc. [source] | ||||||||||