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Michael Reaction (michael + reaction)
Kinds of Michael Reaction Selected AbstractsMichael Reaction of Nitroalkanes with ,-Nitroacrylates under a Solid Promoter: Advanced Regio- and Diastereoselective Synthesis of Nitro-Functionalized ,,,-Unsaturated Esters and 1,3-Butadiene-2-carboxylatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Alessandro Palmieri Abstract A new class of nitro-functionalized ,,,-unsaturated esters has been prepared by a regio- and diastereoselective Michael addition of nitroalkanes to ,-nitroacrylates, performed at room temperature, under carbonate on polymer as promoter, and in the presence of ethyl acetate as eco-friendly solvent. Moreover, by the modular choice of the reaction conditions the method allows the synthesis of 1,3-butadiene-2-carboxylates. [source] Highly Efficient Asymmetric Michael Reaction of Aldehydes to Nitroalkenes with Diphenylperhydroindolinol Silyl Ethers as OrganocatalystsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Ren-Shi Luo Abstract New dihydroindole and perhydroindole derivatives were synthesized in good yields and evaluated as chiral catalysts in the asymmetric Michael reaction of aldehydes to nitroalkenes. (2S,3aS,7aS)-Diphenylperhydroindolinol silyl ether 10 facilitated the reaction of a wide range of aldehyde and nitroalkene substrates, providing Michael adducts in nearly optically pure form (99% ee), good yields and high diastereoselectivities (syn/anti up to 99:1). These results show for the first time that perhydroindole derivatives can also be highly efficient organocatalysts for the asymmetric Michael reaction, exhibiting comparable or even better enantioselectivities than proline derivatives. [source] Primary Amine-Thioureas based on tert -Butyl Esters of Natural Amino Acids as Organocatalysts for the Michael ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Christoforos Abstract A new class of primary amine-thioureas based on tert -butyl esters of (S)-,-amino acids and (1S,2S)-diphenylethylenediamine was synthesized and their activity as catalysts in Michael additions was evaluated. Derivatives based on di- tert -butyl aspartate and tert -butyl O - tert -butyl threoninate provided the product of the reaction between trans- ,-nitrostyrene and acetone in quantitative yield and high enantioselectivity (87,91% ee). All the thioureas based on tert -butyl esters of amino acids catalyzed the reaction of nitroolefins with acetophenone with high enantioselectivity (92,98% ee). Thus, low-cost, commercially available tert -butyl esters of natural amino acids are very important chiral building blocks for the construction of novel chiral thioureas able to catalyze asymmetric Michael additions with high enantioselectivity. [source] ChemInform Abstract: Enantioselective Michael Reaction of ,-Keto Esters Organocatalyzed by Recoverable Cinchona-Derived Dimeric Ammonium Salts.CHEMINFORM, Issue 22 2010Silvia Tari 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] ChemInform Abstract: Highly Efficient Asymmetric Michael Reaction of Aldehydes to Nitroalkenes with Diphenylperhydroindolinol Silyl Ethers as Organocatalysts.CHEMINFORM, Issue 6 2010Ren-Shi Luo 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] ChemInform Abstract: Synthesis of Homoproline Analogues Containing Heterocyclic Rings and Their Activity as Organocatalysts for Michael Reaction.CHEMINFORM, Issue 38 2009Efrosini Barbayianni 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 Enantioselective Mukaiyama,Michael Reaction of 2-(Trimethylsilyloxy)furan with ,,-Phenylsulfonyl Enones.CHEMINFORM, Issue 27 2008Hyeyeon Yang 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] Asymmetric Michael Reaction: Novel Efficient Access to Chiral ,-Ketophosphonates (III).CHEMINFORM, Issue 34 2007Sandrine Delarue-Cochin 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] Creation of Monomeric La Complexes on Apatite Surfaces and Their Application as Heterogeneous Catalysts for Michael Reaction.CHEMINFORM, Issue 19 2006Kohsuke Mori 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] Cysteine-Derived Organocatalyst in a Highly Enantioselective Intramolecular Michael Reaction.CHEMINFORM, Issue 13 2006Yujiro Hayashi 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] ZrCl4 -Catalyzed Michael Reaction of 1,3-Dicarbonyls and Enones under Solvent-Free Conditions.CHEMINFORM, Issue 33 2005G. Smitha Abstract For Abstract see ChemInform Abstract in Full Text. [source] Construction of C,S Bonds with a Quaternary Stereocenter Through a Formal Michael Reaction: Asymmetric Synthesis of Tertiary Thiols.CHEMINFORM, Issue 41 2004Claudio Palomo Abstract For Abstract see ChemInform Abstract in Full Text. [source] Asymmetric Michael Reaction Between a Chiral ,,,-Dimethyl-,-enamino Ester and ,-Substituted Acrylates.CHEMINFORM, Issue 28 2004Frederic Hendra Abstract For Abstract see ChemInform Abstract in Full Text. [source] Self-Catalytic Michael Reaction of Enolizable Carbonyl Compounds.CHEMINFORM, Issue 10 2004-Methylene-, -valerolactones., A Facile Route to Abstract For Abstract see ChemInform Abstract in Full Text. [source] Highly Enantioselective Construction of Quaternary Stereocenters on ,-Keto Esters by Phase-Transfer Catalytic Asymmetric Alkylation and Michael Reaction.CHEMINFORM, Issue 51 2003Takashi Ooi Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Quantitative Synthesis of ,-Carboxylated Thiolophosphates via a Michael Reaction.CHEMINFORM, Issue 45 2003Elisabeth Desforges Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Asymmetric Michael Reaction of Diethyl Malonate with Crotonaldehyde Catalyzed by Chiral Aminocarboxylates, Amino Alcoholates, and Amino Phenolates.CHEMINFORM, Issue 23 2002K. A. Kochetkov 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] Ionic Liquids Made with Dimethyl Carbonate: Solvents as well as Boosted Basic Catalysts for the Michael ReactionCHEMISTRY - A EUROPEAN JOURNAL, Issue 45 2009Massimo Fabris Dr. Abstract This article describes 1),a methodology for the green synthesis of a class of methylammonium and methylphosphonium ionic liquids (ILs), 2),how to tune their acid,base properties by anion exchange, 3),complete neat-phase NMR spectroscopic characterisation of these materials and 4),their application as active organocatalysts for base-promoted carbon,carbon bond-forming reactions. Methylation of tertiary amines or phosphines with dimethyl carbonate leads to the formation of the halogen-free methyl-onium methyl carbonate salts, and these can be easily anion-exchanged to yield a range of derivatives with different melting points, solubility, acid,base properties, stability and viscosity. Treatment with water, in particular, yields bicarbonate-exchanged liquid onium salts. These proved strongly basic, enough to efficiently catalyse the Michael reaction; experiments suggest that in these systems the bicarbonate basicity is boosted by two orders of magnitude with respect to inorganic bicarbonate salts. These basic ionic liquids used in catalytic amounts are better even than traditional strong organic bases. The present work also introduces neat NMR spectroscopy of the ionic liquids as a probe for solute,solvent interactions as well as a tool for characterisation. Our studies show that high catalytic efficacy of functional ionic liquids can be achieved by integrating their green synthesis, along with a fine-tuning of their structure. Demonstrating that ionic liquid solvents can be made by a truly green procedure, and that their properties and reactivity can be tailored to the point of bridging the gap between their use as solvents and as catalysts. [source] Nickel Complexes of N/O -Functionalized N-Heterocyclic Carbenes as Precatalysts for Michael Reactions in Air at Room Temperature Under the Much Preferred Base-Free ConditionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2009Sriparna Ray Abstract A series of several new nickel precatalysts supported overN/O -functionalized N-heterocyclic carbenes (NHC) for the Michael reactions of ,-dicarbonyl, ,-keto ester, ,-diester, and ,-cyano ester compounds with ,,,-unsaturated carbonyl compounds in air at ambient temperature under the much preferred base-free conditions are reported. Specifically, the nickel complexes, [1-(R1 -aminocarbonylmethyl)-3-R2 -imidazol-2-ylidene]2Ni [R1 = 2-C6H4(OMe); R2 = Me (1b), iPr (2b), CH2Ph (3b) and R1 = 2-CH2C4H3O; R2 = Me (4b), CH2Ph (5b)] carried out the highly convenient base-free Michael addition of the activated C,H compounds across ,,,-unsaturated carbonyl compounds in air at room temperature. The complexes 1b,5b were synthesized by the direct reaction of the respective imidazolium chloride salt with NiCl2·6H2O in CH3CN in the presence of K2CO3 as a base. The exceptional stability of 1b,5b has been attributed to the deeply buried nickel,NHC ,-bonding molecular orbitals as evidenced from the density functional theory (DFT) studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Synthesis and Characterisation of New Iridium Complexes with the (4S)-2-[2-(Diphenylphosphanyl)phenyl]-4-isopropyl-1,3-oxazoline Ligand That Catalyse Asymmetric Michael ReactionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2005Daniel Carmona Abstract The chiral iridium compounds [IrCl(COE){(S)-PN}] {COE = cyclooctene, PN = (4S)-2-[2-(diphenylphosphanyl)phenyl]-4-isopropyl-1,3-oxazoline, (1)}, [Ir(acac)ClH{(S)-PN}] {Hacac = acetylacetone, (2)} and [Ir{(S)-PN}2]A {A = Cl (3a,b); BF4 (4a,b); PF6 (5a,b)} have been prepared, characterised and employed as catalysts for the asymmetric Michael addition of keto or cyano esters to ,,,-unsaturated carbonyl compounds. The X-ray molecular structures of compounds 2 and 5b are reported. The model catalytic intermediates [IrH(NCCHCO2R){(S)-PN}2]Cl {R = Me (12), Et (13)} have also been isolated and characterised. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Transition States of the Asymmetric Michael Reactions of Aldehydes Catalyzed by Trimethylsilyl-Protected DiphenylprolinolEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2009Jian-Qiang Zhao Abstract The asymmetric Michael reactions of aldehydes and nitroalkenes catalyzed by trimethylsilyl-protected diphenylprolinol were investigated by using density functional theory calculations. As a result of the stereospecific blockade of the bulky diphenylsiloxymethyl group on the pyrrolidine ring, the Re face of the enamine double bond is effectively shielded. For acetaldehyde, there are two different conformers of the enamine intermediate. On the basis of the two conformers of the enamine intermediate, four different reaction pathways were considered and four different transition states were searched for the enantioselective asymmetric Michael reaction of acetaldehyde and nitroalkene. The lowest- and second-lowest-energy transition states are both formed via the same intermediate IM2. The enantiomeric excess, calculated to be 96,%,ee, is in good agreement with the experimental value. For propanal, on the basis of the four different conformers of the prolinol,enamine intermediate, eight different reaction pathways were considered and eight transition states were searched for the enantioselective asymmetric Michael reaction. The calculated ee value is 99.5,%, which is in good agreement with the experimental ee value of 99,%. The lowest- and second-lowest-energy transition states are formed via different enamine intermediates, which is different from the case of acetaldehyde. The calculations also reveal that the intermediates play an important role in the reactions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] anti -Selective Asymmetric Michael Reactions of Aldehydes and Nitroolefins Catalyzed by a Primary Amine/Thiourea,ANGEWANDTE CHEMIE, Issue 52 2009Hisatoshi Uehara Dr. "anti" geht auch: Hoch anti -selektive Michael-Reaktionen eines funktionalisierten Aldehyds mit Nitroolefinen gelangen in Gegenwart eines Katalysators mit primärer Amino- und Thioharnstoff-Funktion (siehe Schema; TBS=tert -Butyldimethylsilyl). Die Reaktion beruht auf der Bildung eines Z -konfigurierten Enamin-Intermediats. [source] Bifunctional Guanidine via an Amino Amide Skeleton for Asymmetric Michael Reactions of ,-Ketoesters with Nitroolefins: A Concise Synthesis of Bicyclic ,-Amino Acids,ANGEWANDTE CHEMIE, Issue 44 2009Zhipeng Yu No abstract is available for this article. [source] ChemInform Abstract: Catalytic, Asymmetric Michael Reactions of Cyclic Diketones with ,,,-Unsaturated ,-Ketoesters.CHEMINFORM, Issue 40 2009Michael A. Calter 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: Rare [(NHC)2Ni-OH]-Type Terminal Nickel Hydroxo and [(NHC)2Ni]-Type Complexes of N/O-Functionalized N-Heterocyclic Carbenes as Precatalysts for Highly Desirable Base-Free Michael Reactions in Air at Ambient Temperature.CHEMINFORM, Issue 35 2009Manoja K. Samantaray 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: Highly Enantio- and Diastereoselective Organocatalytic Cascade Aza-Michael,Michael Reactions: A Direct Method for the Synthesis of Trisubstituted Chiral Pyrrolidines.CHEMINFORM, Issue 14 2009Hao Li 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: Michael Reactions of ,-Ketoesters Catalyzed by Yb(NTf2)3 in the Presence of Water.CHEMINFORM, Issue 51 2008Ichiro Suzuki 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] Cu(I) Tol-BINAP-Catalyzed Enantioselective Michael Reactions of Grignard Reagents and Unsaturated Esters.CHEMINFORM, Issue 23 2007Shun-Yi Wang 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] Amine-Catalyzed Michael Reactions of an Aminoaldehyde Derivative to Nitroolefins.CHEMINFORM, Issue 18 2007Klaus Albertshofer 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] Convenient "One-Pot" Synthesis of 3,4-Substituted Tetrahydrothiophenes Through Tandem Michael,Henry and Michael,Michael Reactions.CHEMINFORM, Issue 8 2007Achille Barco 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] | |||||||||||||||||||||||||