			Home About us Contact

Terminal Alkenes (terminal + alkene)

Distribution by Scientific Domains

Chemistry	100%

Selected Abstracts

Cover Picture: Bidentate Ligands by Self-Assembly through Hydrogen Bonding: A General Room Temperature/Ambient Pressure Regioselective Hydroformylation of Terminal Alkenes (Adv. Synth.

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-13 2005
Catal.
Abstract The cover picture shows a typical industrial reaction, hydroformylation of terminal alkenes, made possible in a test tube with ambient pressure and room temperature with high regioselectivities. For more details, see the Communication by Wolfgang Seiche, Alexander Schuschkowski, and Bernhard Breit on pages 1488,1494. [source]

Stereoselective Iodocyclopropanation of Terminal Alkenes with Iodoform, Chromium(II) Chloride, and N,N,N,,N,-Tetraethylethylenediamine.

CHEMINFORM, Issue 10 2004
Kazuhiko Takai
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Enantioselective Epoxidation of Terminal Alkenes to (R)- and (S)-Epoxides by Engineered Cytochromes P450 BM-3

CHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2006
Takafumi Kubo
Abstract Cytochrome P450 BM-3 from Bacillus megaterium was engineered for enantioselective epoxidation of simple terminal alkenes. Screening saturation mutagenesis libraries, in which mutations were introduced in the active site of an engineered P450, followed by recombination of beneficial mutations generated two P450 BM-3 variants that convert a range of terminal alkenes to either (R) - or (S) - epoxide (up to 83,% ee) with high catalytic turnovers (up to 1370) and high epoxidation selectivities (up to 95,%). A biocatalytic system using E. coli lysates containing P450 variants as the epoxidation catalysts and in vitro NADPH regeneration by the alcohol dehydrogenase from Thermoanaerobium brockii generates each of the epoxide enantiomers, without additional cofactor. [source]

Palladium-Catalyzed Cyclopropanation of Alkenyl Silanes by Diazoalkanes: Evidence for a Pd0 Mechanism

CHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2009
Guillaume Berthon-Gelloz Dr.
Abstract Pd0does the trick! Alkenyl silanes are efficiently cyclopropanated by diazoalkanes at low Pd loadings (see scheme). Clear evidence for the involvement of a Pd0 resting state for this reaction is given. Alkenyl silanes are efficiently converted to the corresponding silyl cyclopropanes in the presence of a slight excess of diazomethane (2,4,equiv) and a low loading of Pd(OAc)2 (<0.5,mol,%). Diazoethane and diazobutane can also be employed and yield silyl cyclopropanes with diastereoselectivities of up to 10:1 for the trans isomer. When conducted on a 4,g scale, the reaction only required a catalyst loading of 5×10,3,mol,%, which corresponds to a turnover frequency of 40,000,h,1. Competition experiments revealed that vinyl silanes can be selectively cyclopropanated in the presence of an aliphatic terminal alkene and styrene. The complex [Pd02(DVTMS)3] (38, DVTMS=divinyltetramethyldisiloxane) proved to be an exceptionally active catalyst for the cyclopropanation reaction, giving complete conversion at ,35,°C in 1,min. Intermolecular and intramolecular competition experiments with DVTMS (36), both with Pd(OAc)2 and 38, provided strong evidence for a Pd0(alkenyl silane)3 resting state. Detailed density functional calculations on the reaction pathways for the cyclopropanation of trimethylvinylsilane and DVTMS by diazomethane with Pd0 corroborated the experimental observations. [source]

Cover Picture: Bidentate Ligands by Self-Assembly through Hydrogen Bonding: A General Room Temperature/Ambient Pressure Regioselective Hydroformylation of Terminal Alkenes (Adv. Synth.

The Multi-Substrate Screening of Asymmetric Catalysts

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2005
Tummanapalli Satyanarayana
Abstract The principle of the one-pot multi-substrate screening is presented. This methodology has been successfully applied to various types of catalyzed enantioselective reactions: borane reduction of ketones, addition of organozinc on aldehydes, conjugate addition of diethylzinc on cycloalkenones or nitroalkenes, hydroformylation of olefins, hetero-Diels,Alder reaction on ,-keto esters, enzymatic hydrolysis of glycerol-type monoesters as well as hydrogenation of 2-aryl-substituted terminal alkenes and enamides. The one-pot multi-catalyst screening methodology is also briefly discussed. [source]

Utilisation of C2,C4 gaseous hydrocarbons and isoprene by microorganisms

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2006
Jean L Shennan
Abstract Microorganisms able to grow on low molecular weight aliphatic hydrocarbon gases, i.e. the n -alkanes, ethane, propane and butane, and the terminal alkenes, ethylene, propylene and butylene, are not uncommon but mainly belong to certain taxonomic groups. These microbes are described in this review together with the pathways by which the hydrocarbons are assimilated. Microbial oxidation of the volatile alkadiene, isoprene, is also discussed. Avenues for possible commercial exploitation of these metabolic activities are also reviewed. Short-chain n -alkane-utilising organisms have been investigated as tools in petroleum exploration and for production of single cell protein. More recently microbes grown on gaseous hydrocarbons other than methane have been evaluated for use in biotechnological production of epoxides, synthesis of chiral epoxyalkanes and as catalysts in bioremediation systems. Copyright © 2005 Society of Chemical Industry [source]

ChemInform Abstract: Adaptative Biaryl Phosphite,Oxazole and Phosphite,Thiazole Ligands for Asymmetric Ir-Catalyzed Hydrogenation of Alkenes.

CHEMINFORM, Issue 32 2010
Javier Mazuela
Abstract A library of 17 chiral ligands is examined in the iridium-catalyzed hydrogenation of (E)- and (Z)-trisubstituted, and 1,1-disubstituted terminal alkenes. [source]