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Michael Addition Reactions (michael + addition_reaction)
Kinds of Michael Addition Reactions Selected AbstractsAsymmetric Michael Addition Reaction of 3-Substituted Oxindoles to Nitroolefins Catalyzed by a Chiral Alkyl- Substituted Thiourea CatalystADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Xin Li Abstract A simple alkylthiourea was found to be an effective catalyst for the Michael addition reaction of 3-substituted oxindole to nitroolefins. A number of 3,3,-substituted oxindole derivatives, which have two vicinal quaternary-tertiary chiral centers were synthesized with up to 99% yield, 19:1 dr and 98% ee. [source] ChemInform Abstract: Asymmetric Michael Addition Reaction of 3-Substituted Oxindoles to Nitroolefins Catalyzed by a Chiral Alkyl-Substituted Thiourea Catalyst.CHEMINFORM, Issue 26 2010Xin Li 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 Michael Addition Reaction of Amines Catalyzed by Silica-Supported Aluminum Chloride.CHEMINFORM, Issue 33 2009Mohammad R. Saidi 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] Highly Enantioselective Michael Addition Reactions of 3-Substituted Benzofuran-2(3H)-ones to Chalcones Catalyzed by a Chiral Alkyl-Substituted ThioureaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Xin Li Abstract A highly enantioselective Michael addition of 3-substituted benzofuran-2(3H)-ones to chalcones catalyzed by a chiral bifunctional thiourea was developed. Several chiral 3,3,-substituted benzofuran-2(3H)-ones derivatives, bearing adjacent quaternary-tertiary stereocenters, were efficiently synthesized with excellent enantioselectivities. [source] ChemInform Abstract: Efficient Direct Asymmetric Vinylogous Michael Addition Reactions of ,-Butenolides to Chalcones Catalyzed by Vicinal Primary-Diamine Salts.CHEMINFORM, Issue 30 2010Junfeng Wang 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 Enantioselective Michael Addition Reactions in Water Catalyzed by an Insoluble MPS-Supported 4-Sulfonamidyl Prolinol tert-Butyldiphenylsilyl Ether.CHEMINFORM, Issue 39 2009Yongming Chuan 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: Pyrrolidine-Based Chiral Pyridinium Ionic Liquids (ILs) as Recyclable and Highly Efficient Organocatalysts for the Asymmetric Michael Addition Reactions.CHEMINFORM, Issue 24 2008Bukuo Ni 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: Hydrogen-Bond-Promoted C,C Bond-Forming Reaction: Catalyst-Free Michael Addition Reactions in Ethanol.CHEMINFORM, Issue 20 2008Seiji Shirakawa 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: Organocatalysts Wrapped Around by Poly(ethylene glycol)s (PEGs): A Unique Host,Guest System for Asymmetric Michael Addition Reactions.CHEMINFORM, Issue 10 2008Dan Qian Xu 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] Highly Enantioselective Organocatalytic Michael Addition Reactions of Ketones with Chalcones.CHEMINFORM, Issue 27 2006Jian 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] ChemInform Abstract: Double Michael Addition Reactions of Some New 1,5-Diaryl-2-alkyl-1,4-pentadien-3-ones.CHEMINFORM, Issue 49 2001Part 2. 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] Chiral Squaramides as Highly Enantioselective Catalysts for Michael Addition Reactions of 4-Hydroxycoumarins and 4-Hydroxypyrone to ,,,-Unsaturated ,-Keto EstersCHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2010Dan-Qian Xu Prof. Distance brings forth beauty: The first highly enantioselective organocatalytic Michael addition of 4-hydroxycoumarins and the analogous 4-hydroxy-6-methyl-2-pyrone to ,,,-unsaturated ,-keto esters by using chiral squaramides as the organocatalysts is disclosed. The efficiency of the process is attributed to the hydrogen-bonding activation (see scheme). [source] Diastereo- and Enantioselective Catalytic Tandem Michael Addition/Mannich Reaction: Access to Chiral Isoindolinones and Azetidines with Multiple Stereocenters,ANGEWANDTE CHEMIE, Issue 15 2010Shengmei Guo Michael und Mannich arbeiten zusammen: Ein schneller und verlässlicher Zugang zu hochfunktionalisierten chiralen Isoindolindon- und Azetidinderivaten mit mehreren benachbarten Stereozentren wird vorgestellt (siehe Schema). [source] Organocatalytic Asymmetric Michael Addition of Pyrazolin-5-ones to Nitroolefins with Bifunctional Thiourea: Stereocontrolled Construction of Contiguous Quaternary and Tertiary StereocentersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010Yu-Hua Liao Abstract The first organocatalytic diastereo- and enantioselective Michael addition reaction of 4-substituted-pyrazolin-5-ones to nitroolefins has been developed with a chiral bifunctional thiourea as organocatalyst. A wide variety of desired multi-substituted pyrazolin-5-one derivatives with contiguous quaternary and tertiary stereocenters are smoothly obtained in very good yields (up to 98%) with excellent enantioselectivities (up to>99% ee) and acceptable diastereoselectivities (up to 80:20). This experimentally simple process facilitates the access to various enantioenriched, multiply substituted pyrazolin-5-one derivatives, potential biologically active molecules, starting from readily available starting materials. [source] Asymmetric Michael Addition Reaction of 3-Substituted Oxindoles to Nitroolefins Catalyzed by a Chiral Alkyl- Substituted Thiourea CatalystADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Xin Li Abstract A simple alkylthiourea was found to be an effective catalyst for the Michael addition reaction of 3-substituted oxindole to nitroolefins. A number of 3,3,-substituted oxindole derivatives, which have two vicinal quaternary-tertiary chiral centers were synthesized with up to 99% yield, 19:1 dr and 98% ee. [source] Enantioselective Michael Addition of Dicyanoolefins to ,,,-Unsaturated Aldehydes in Aqueous MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2008Jun Lu Abstract A pool of water-compatible catalysts, namely dialkyl-(S)-prolinols, has been developed for the enantioselective direct vinylogous Michael addition reaction of vinylmalononitriles to ,,,-unsaturated aldehydes in aqueous medium. In many cases, the products can be obtained in almost optically pure form (>96% ee) after a single recrystallization. [source] Synthesis of novel moisture-curable polyurethanes end-capped with trialkoxysilane and their application to one-component adhesivesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2007Yukihiro Nomura Abstract Novel silane endcappers and novel polyurethanes end-capped with trimethoxysilane (silylated polyurethanes) were developed as water-curable materials in which the curing reaction occurred under humid conditions in the presence of dioctyltin diversatate as a curing catalyst. A variety of amine-terminated trimethoxysilane compounds were synthesized by the Michael addition reaction of commercially available 3-aminopropyltrimethoxysilane with acrylates, and the resulting silane endcappers were used to react with isocyanate-terminated polyurethanes, providing the silylated polyurethanes. The moisture-curable silylated polyurethanes were used for the preparation of novel one-component and solvent-free adhesives. The evaluated properties were the curing speed, the tensile shear bond strength, and the adherence to some substrates. The longer alkyl chains of the silane endcappers derived from various acrylates led to a slower curing speed, lower tensile strength at break, and longer elongation at break of the silylated polyurethanes. The tensile shear bond strength of the silylated polyurethane-based adhesive decreased with decreasing the trimethoxysilane end-capping ratio, whereas an increase in the adherence was observed. The adherence to the acrylic substrate was improved by changes in the main-chain structure of the polyurethane based on the composition of poly(propylene oxide) and poly(ethylene oxide). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2689,2704, 2007 [source] One-pot synthesis of linear and branched poly(amide aspartimide)s with good solubility in organic solventsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2005Chuan-Shao Wu Abstract Linear and branched poly(amide aspartimide)s were prepared through the reaction of 4,4,-diaminodiphenylmethane with 4-maleimidobenzoic acid and 5-maleimidoisophthalic acid, respectively. The synthesis was performed through a one-pot operation by means of the Michael addition reaction between amine and maleimide groups and the dehydration condensation reaction between amine and carboxylic acid groups. The obtained polymers exhibited fairly good solubility in aprotic polar solvents at room temperature and in pyridine, tetrahydrofuran, acetone, and chloroform upon heating. High glass-transition temperatures (,225 °C) and thermal stability above 360 °C were found for the polymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1923,1929, 2005 [source] Unexpected Crosslinking During Acetoacetoxy Group Protection on Waterborne Crosslinkable LatexesMACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2006Iñigo González Abstract Summary: The microstructure of the polymer synthesized by seeded semicontinuous emulsion copolymerization of AAEMA was investigated. It was found that the neutralization of the latexes with ammonia to protect acetoacetoxy functionality against hydrolysis during storage had a remarkable effect on the gel content. A base catalyzed Michael addition reaction between acetoacetoxy groups and terminal double bond (TDB) is proposed as responsible for the chain precrosslinking observed. The presence of TDB in the latexes was demonstrated by means of 1H NMR. Moreover, the chain precrosslinking affected the subsequent crosslinking reaction of the latex with diamines hindering chain interdiffusion and yielding poorer mechanical properties. Michael addition between AcAc functional groups and TDB, and final gel content of the MMA/BA/MAA latexes with different amounts of AAEMA. [source] Chiral guanidine catalyzed Michael addition reaction and Diels-Alder reaction of anthrone and N -methylmaleimideCHINESE JOURNAL OF CHEMISTRY, Issue 3 2000Peng Bin Abstract Two chiral guanidines were evaluated as catalysts for the reaction of anthrone (1) with N -methylmaleimide (2). When guanidine 5 was used, the Michael adduct 4 was isolated as a major product. The best enantioselectivity (70% ee) was obtained when the reaction was carried out in THF at -20°C. [source] Quantitative structure,reactivity relationship studies on the catalyzed Michael addition reactionsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 6 2009Bahram Hemmateenejad Abstract Quantitative structure,reactivity relationship (QSRR) can be considered as a variant of quantitative structure,property relationship (QSPR) studies, where the chemical reactivity of reactants or catalysts in a specified chemical reaction is related to chemical structure. In this manner, the Michael addition of some different substrates using different catalysts (SDS, silica gel, and ZrOCl2) was subjected to structure,reactivity relationship, quantitatively. Multiple linear regression (MLR) and partial least square (PLS) were used to perform the QSRR analysis. The resulted models for different catalyzed reactions showed that the catalysts probably act in different mechanisms since the models obtained for the catalysts included different parameters from substrate and enones. Overall, it was found that the reactivity in Michael addition reactions is controlled by coulombic (dipole and charge) interactions as well as the orbital energetic parameters. In the presence of different catalysts, the relative importance of these parameters is changed and hence the catalytic activity is changed. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||