نتایج جستجو برای: alkene epoxidation

تعداد نتایج: 3643  

Journal: :Angewandte Chemie 2016
Ivan Buslov Fang Song Xile Hu

The first efficient and non-precious nanoparticle catalyst for alkene hydrosilylation with commercially relevant tertiary silanes has been developed. The nickel nanoparticle catalyst was prepared in situ from a simple nickel alkoxide precatalyst Ni(O(t) Bu)2 ⋅x KCl. The catalyst exhibits high activity for anti-Markovnikov hydrosilylation of unactivated terminal alkenes and isomerizing hydrosily...

2011
Jesús Pastrán Andrea Ramírez Giuseppe Agrifoglio Anthony Linden Romano Dorta

In the crystal structure of the title ketoamine, C(19)H(29)NO, the bond lengths from the N atom through the alkene group to the ketone O atom show the presence of an extensively delocalized π-system. The dihedral angle between the plane of the phenyl ring and that of the alkene component is 63.45 (7)° due to steric hindrance exerted by the tert-butyl groups. The mol-ecule has a Z-configured alk...

Journal: :Journal of the American Chemical Society 2005
Frank Hollmann Karin Hofstetter Tilo Habicher Bernhard Hauer Andreas Schmid

We report the first example of direct electrochemical regeneration of a flavin-dependent monooxygenase for asymmetric epoxidation catalysis. It is shown that electrochemical regeneration of the oxygenase subunit of the multicomponent styrene monooxygenase is sufficient to perform enantiospecific S-epoxidation of various styrene derivatives. Kinetic bottlenecks of the novel electroenzymatic reac...

Journal: :Chemical communications 2014
Charles-Oneil L Crites Geniece L Hallet-Tapley María González-Béjar J C Netto-Ferreira Juan C Scaiano

The catalytic epoxidation of cis-stilbene using cumene as a solvent in the presence of supported gold nanoparticles (AuNP) yields a mixture of cis and trans-stilbene oxides. EPR and product distribution studies support a new mechanistic proposal where oxygen centred radicals activate the AuNP surface and form active surface oxygen species responsible for the epoxidation products.

Journal: :Journal of the American Chemical Society 2010
Tejas P Pathak Keith M Gligorich Bryan E Welm Matthew S Sigman

A unique alkene difunctionalization reaction that allows rapid construction of molecular complexity around the biologically relevant indole framework has been developed. The reaction proceeds with up to 87% yield, 99:1 er, and >20:1 dr. Evaluation of several of the compounds revealed promising anticancer activity against MCF-7 cells.

Journal: :Organic & biomolecular chemistry 2014
Xiubing Liu Lingling Hu Xiaojing Liu Junhao Jia Lizhen Jiang Jiangfeng Lin Xiaochuan Chen

A useful and flexible strategy for synthesis of (-)- and (+)-infectocaryone from commercial sugars is developed. The key step of the synthesis is a new-type Diels-Alder reaction with good chemoselectivity and stereoselectivity, in which a mixture of alkene regioisomers in a dynamic equilibrium is employed as chiral dienophiles for the first time.

Journal: :Insect biochemistry and molecular biology 2011
L A Defelipe E Dolghih A E Roitberg M Nouzova J G Mayoral F G Noriega A G Turjanski

Juvenile hormones (JHs) play key roles in regulating metamorphosis and reproduction in insects. The last two steps of JH synthesis diverge depending on the insect order. In Lepidoptera, epoxidation by a P450 monooxygenase precedes esterification by a juvenile hormone acid methyltransferase (JHAMT). In Orthoptera, Dictyoptera, Coleoptera and Diptera epoxidation follows methylation. The aim of ou...

Journal: :Organic & biomolecular chemistry 2012
Nathaniel Martin Eric J Thomas

Two syntheses of the C(7)–C(16)-fragment 41 of epothilone D 2 were developed that were based on tin(IV) bromide mediated reactions of 5,6-difunctionalised hex-2-enylstannanes with aldehydes. In the first synthesis, (5S)-6-tert-butyldimethylsilyloxy-5-hydroxy-2-methylhex-2-enyl(tributyl)stannane 20 was reacted with (E)-but-2-enal to give (2S,7R,4Z,8E)-1-tert-butyldimethylsilyloxy-5-methyldeca-4,...

Journal: :Angewandte Chemie 2011
Ranjan Jana James J Partridge Jon A Tunge

A three-component coupling of vinyl triflates and boronic acids to alkenes catalyzed by palladium is reported. Using 1,3-dienes, selective 1,2-alkene difunctionalization is observed, whereas the use of terminal alkenes results in 1,1-alkene difunctionalization. The reaction outcome is attributed to the formation of stabilized, cationic Pdπ-allyl intermediates to regulate β-hydride elimination. ...

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