نتایج جستجو برای: benzoin

تعداد نتایج: 326  

Journal: :Organic & biomolecular chemistry 2011
Fang-gang Sun Song Ye

The diastereoselective synthesis of cis-2-amino-3-hydroxyindanones was realized by the N-heterocyclic carbene-catalyzed [4 + 1] annulation of phthalaldehyde and imines, which may involve a tandem aza-benzoin reaction and aldol reaction.

Journal: :Journal of Photopolymer Science and Technology 1990

Journal: :Organic & biomolecular chemistry 2011
Zsolt Kelemen Oldamur Hollóczki József Nagy László Nyulászi

The carbene concentration in 1-ethyl-3-methylimidazolium-acetate ionic liquid is sufficiently high to act as a catalyst in benzoin condensation, hydroacylation and also in oxidation of an alcohol by using CO(2) and air. This observation reveals the potential of ionic liquid organocatalysts, uniting the beneficial properties of these two families of compounds.

Journal: :Chemical communications 2010
Dieter Enders André Grossmann Jeanne Fronert Gerhard Raabe

A new triazolium salt derived N-heterocyclic carbene catalyses an asymmetric cross-benzoin-type reaction of heteroaromatic aldehydes and various trifluoromethyl ketones in good to excellent yields (69-96%) and moderate to good enantioselectivities (ee = 39-85%). Up to 99% ee can be achieved by recrystallisation.

Journal: :Organic & biomolecular chemistry 2009
Sarah E O'Toole Stephen J Connon

The design of a new class of triazolium ion precatalysts incorporating protic substituents is described. These materials promote the enantioselective benzoin condensation of a range of aromatic aldehydes (1-62% ee). Catalyst evaluation studies strongly support the involvement of hydrogen bond donation by the catalyst in the stereocentre-forming step of the catalytic cycle.

2015
Julia Rehbein Stephanie-M. Ruser Jenny Phan

The Breslow catalytic cycle describing the benzoin condensation promoted by N-heterocyclic carbenes (NHC) as proposed in the late 1950s has since then been tried by generations of physical organic chemists. Emphasis has been laid on proofing the existence of an enaminol like structure (Breslow intermediate) that explains the observed umpolung of an otherwise electrophilic aldehyde. The present ...

Journal: :Electrophoresis 2003
Simon Mwongela Cevdet Akbay Xiaofeng Zhu Sibrina Collins Isiah M Warner

A chiral amino acid-based monomeric and polymeric surfactant, sodium oleyl-L-leucylvalinate) (L-SOLV) and poly(sodium oleyl-L-leucylvalinate) (poly-L-SOLV) were synthesized and used for chiral separations in micellar electrokinetic chromatography (MEKC). Poly-L-SOLV was used successfully in the separation of various enantiomers of neutral, acidic, and basic analytes such as 1,1'-bi-2-napthol, 1...

Journal: :Journal of the American Chemical Society 2017
Fan Cui Letian Dou Qin Yang Yi Yu Zhiqiang Niu Yuchun Sun Hao Liu Ahmad Dehestani Kerstin Schierle-Arndt Peidong Yang

In this work, we report a new, general synthetic approach that uses heat driven benzoin radicals to grow ultrathin copper nanowires with tunable diameters. This is the first time carbon organic radicals have been used as a reducing agent in metal nanowire synthesis. In-situ temperature dependent electron paramagnetic resonance (EPR) spectroscopic studies show that the active reducing agent is t...

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