نتایج جستجو برای: heck cross

تعداد نتایج: 491365  

Journal: :Organic letters 2016
Zhantao Yang Xiaolong Xu Chun-Hua Yang Yunfeng Tian Xinyi Chen Lihui Lian Wenwei Pan Xuncheng Su Weicheng Zhang Yue Chen

Nannocystin A is a 21-membered cyclodepsipeptide showing remarkable anticancer properties. Described is the total synthesis of nannocystin A, which features an asymmetric vinylogous Mukaiyama aldol reaction for efficient assembly of the penultimate open-chain precursor and a pivotal intramolecular Heck cross-coupling for the final macrocyclization.

Journal: :Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2007
Francesco Babudri Gianmarco Bilancia Antonio Cardone Paolo Coppo Luisa De Cola Gianluca M Farinola Johannes W Hofstraat Francesco Naso

A conjugated alternating copolymer containing norbornadiene and bis(ethynylene)phenylene units was prepared by the Cassar-Heck-Sonogashira cross-coupling reaction. Its electroluminescence was tested in a device, and its fluorescence colour could be tuned by light-induced norbornadiene-quadricyclane isomerization.

Journal: :Chemical communications 2011
Jianli Zou Scott G Stewart Colin L Raston K Swaminathan Iyer

Palladium nano-crystals increase in size during the initial recycling in Heck cross coupling reactions. We demonstrate that oxygen adsorbed on the surface of palladium nano-crystals plays a pivotal role in driving the ripening. This in turn is associated with a loss in catalytic activity.

2015
Jerzy Zakrzewski Bogumiła Huras

Cinnamic acid derivatives bearing a nitroxyl moiety (2,2,6,6-tetramethyl-1-oxyl-4-piperidyl 3-E-aryl acrylates) were synthesized in 30-100% yield using a Mizoroki-Heck cross-coupling reaction between 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl and iodobenzene derivatives in the presence of palladium(II) acetate coordinated with a tri(o-tolyl)phosphine ligand immobilized in a polyurea mat...

Journal: :iranian journal of catalysis 2012
abdol hajipour fatemeh abrishami

the application of the [pd{c6h3(ch2ch2nh2)-4-ome-5-κ2-c,n}(μ-br)]2 complex of 2-methoxyphenethylamine in the heck coupling reaction was considered under both conventional and microwave irradiation conditions, and their results were compared. this complex is an efficient, stable and non-sensitive to air and moisture catalyst for the vinylation of substituted aryl halides with different electroni...

Journal: :Chemical communications 2011
Michael Bradshaw Jianli Zou Lindsay Byrne K Swaminathan Iyer Scott G Stewart Colin L Raston

Pd(II)-chitosan composite nanofibres of 62 ± 9 nm diameter are efficient catalysts for Heck cross-coupling reactions. Using a model reaction of iodo-benzene and n-butyl acrylate, we demonstrate that this material can be used as a recyclable catalytic support with a very low loading of palladium (0.17 mol% Pd).

Journal: :Chemical communications 2012
Kyle L Bolduc Scott D Larsen David H Sherman

A flexible and divergent synthesis of cryptophycin unit A analogues is described. This method relies on iridium-catalysed stereo- and enantioselective crotylation and chemoselective one-pot oxidative olefination to access common intermediate . Heck, cross metathesis, and Suzuki-Miyaura reactions are illustrated for the generation of methyl ester unit A analogues .

2017
Tue Heesgaard Jepsen Emil Glibstrup François Crestey Anders A Jensen Jesper Langgaard Kristensen

We report an effective synthetic protocol to access [6,6]-bicyclic lactone moieties through a regio- and stereoselective intramolecular Mizoroki-Heck cross-coupling reaction followed by a 6π-electrocyclization. This method enabled the first synthesis of the elusive CD fragment of the Erythrina alkaloid DHβE. Preliminary pharmacological evaluations support the notion that the key pharmacophores ...

Journal: :iranian journal of catalysis 2015
fatemeh rafiee abdol reza hajipour

a new dimeric orthopalladated complex was synthesized via reaction of 2,3-dimethoxy benzaldehyde oxime with palladium chloride and lithium chloride in methanol as solvent and sodium acetate as base at room temperature. the catalytic activity of this dimeric [pd{c6h2(-ch=noh)-(ome)2-2,3}(µ-cl)]2 complex as an efficient, air, and moisture tolerant catalyst was investigated in mizoroki–heck cross ...

2006
Anders L. Hansen Jean-Philippe Ebran M rten Ahlquist Per-Ola Norrby Troels Skrydstrup

Considerable efforts have been undertaken by numerous groups in academia and industry over the past decade to expand the repertoire of coupling reagents in palladium(0)-catalyzed cross-coupling reactions. In particular, alkenyl phosphates and tosylates have proven their worth in various cross-coupling reactions, such as the Stille, Suzuki, 3] Negishi, Kumada, Sonogashira, b,e,f,5] Buchwald–Hart...

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