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Activated Olefins (activated + olefin)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Dendritic Chiral Phosphine Lewis Bases-Catalyzed Asymmetric Aza-Morita,Baylis,Hillman Reaction of N -Sulfonated Imines with Activated Olefins

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2008
Ying-hao Liu
Abstract A series of polyether dendritic chiral phosphine Lewis bases was synthesized, and successfully applied to the asymmetric aza-Morita,Baylis,Hillman reaction of N -sulfonated imines (N -arylmethylidene-4-methylbenzenesulfonamides) with methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), and acrolein to give the adducts in good to excellent yields along with up to 97,% ee, which are more effective than our previously reported original chiral phosphine Lewis bases. In addition, the dendrimer-supported chiral phosphine Lewis bases can be easily recovered and reused. [source]

ChemInform Abstract: Asymmetric Cyanation of Activated Olefins with Ethyl Cyanoformate Catalyzed by a Modular Titanium Catalyst.

CHEMINFORM, Issue 31 2010
Jun 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: Mild and Efficient Michael Addition of Activated Olefins to Indoles Using TBAB as a Catalyst: Synthesis of 3-Substituted Indoles.

CHEMINFORM, Issue 44 2008
K. Suresh Babu
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: Dendritic Chiral Phosphine Lewis Bases-Catalyzed Asymmetric Aza-Morita,Baylis,Hillman Reaction of N-Sulfonated Imines with Activated Olefins.

CHEMINFORM, Issue 21 2008
Ying-hao Liu
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]

DABCO-Catalyzed Reactions of Hydrazones with Activated Olefins.

CHEMINFORM, Issue 45 2005
Gui-Ling Zhao
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Addition of Electrochemically Prepared Arylzinc Species onto Activated Olefins via a Cobalt Catalysis.

CHEMINFORM, Issue 5 2003
Paulo Gomes
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: Cyclopropane Formation by Copper-Catalyzed Indirect Electroreductive Coupling of Activated Olefins and Activated ,,,,,-Trichloro or gem-Dichloro Compounds.

CHEMINFORM, Issue 30 2002
S. Sengmany
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: Cyclopropane Formation by Nickel-Catalyzed Electroreductive Coupling of Activated Olefins and Unactivated gem-Dibromo Compounds.

CHEMINFORM, Issue 26 2002
Stephane Sengmany
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]

Kinetic Studies of the Oxidative Addition and Transmetallation Steps Involved in the Cross-Coupling of Alkynyl Stannanes with Aryl Iodides Catalysed by ,2 -(Dimethyl fumarate)(iminophosphane)palladium(0) Complexes

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2004
Bruno Crociani
Abstract The complexes [Pd(,2 -dmfu)(P,N)] {dmfu = dimethyl fumarate; P,N = 2-(PPh2)C6H4,1-CH=NR, R = C6H4OMe-4 (1a), CHMe2 (2a), C6H3Me2 -2,6 (3a), C6H3(CHMe2)2 -2,6 (4a)} undergo dynamic processes in solution which consist of a P,N ligand site exchange through initial rupture of the Pd,N bond at lower energy and an olefin dissociation-association at higher energy. According to equilibrium constant values for olefin replacement, the complex [Pd(,2 -fn)(P,N)] (fn = fumaronitrile, 1b) has a greater thermodynamic stability than its dmfu analogue 1a. The kinetics of the oxidative addition of ArI (Ar = C6H4CF3 -4) to 1a and 2a lead to the products [PdI(Ar)(P,N)] (1c, 2c) and obey the rate law, kobs = k1A + k2A[ArI]. The k1A step involves oxidative addition to a reactive species [Pd(solvent)(P,N)] formed from dmfu dissociation. The k2A step is better interpreted in terms of oxidative addition to a species [Pd(,2 -dmfu)(solvent)(,1 -P,N)] formed in a pre-equilibrium step from Pd,N bond breaking. The complexes 1c and 2c react with PhC,CSnBu3 in the presence of an activated olefin (ol = dmfu, fn) to yield the palladium(0) derivatives [Pd(,2 -ol)(P,N)] along with ISnBu3 and PhC,CAr. The kinetics of the transmetallation step, which is rate-determining for the overall reaction, obey the rate law: kobs = k2T[PhC,CSnBu3]. The k2T values are markedly enhanced in more polar solvents such as CH3CN and DMF. The solvent effect and the activation parameters suggest an associative SE2 mechanism with substantial charge separation in the transition state. The kinetic data of the above reactions in various solvents indicate that, for the cross-coupling of PhC,CSnBu3 with ArI catalysed by 1a or 2a, the rate-determining step is represented by the oxidative addition and that CH3CN is the solvent in which the highest rates are observed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

1,3,5-Triaza-7-phosphaadamantane (PTA): A Practical and Versatile Nucleophilic Phosphine Organocatalyst

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2007
Xiaofang Tang
Abstract In this paper, the air-stable and readily available 1,3,5-triaza-7-phosphaadmantane (PTA) is reported as a practical and versatile nucleophilic phosphine organocatalyst. Under the mediation of 15,30 mol,% of PTA, various electrophiles like aldehydes and imines readily undergo the Morita,Baylis,Hillman reactions with a variety of activated olefins, giving the corresponding adducts in high yields. In the phosphine-catalyzed [3+2] cycloaddition reaction of 4-substituted 2,3-butadienoates with N -tosylimines, PTA is also proven to be a comparable catalyst as tributylphosphine (PBu3). By systematic comparison with other structurally similar N,P catalysts, it is concluded that the superiority of PTA in the above nucleophilic catalysis is attributable to its comparable nucleophilicity with that of trialkylphosphines. The feasibility to use PTA as an alternative catalyst in place of the air-sensitive trialkylphosphines is also discussed. [source]