نتایج جستجو برای: henry reaction

تعداد نتایج: 421222  

Journal: :Molecules 2015
Marleen Häring Maria M Pérez-Madrigal Dennis Kühbeck Asja Pettignano Françoise Quignard David Díaz Díaz

In this manuscript we report a critical evaluation of the ability of natural DNA to mediate the nitroaldol (Henry) reaction at physiological temperature in pure water. Under these conditions, no background reaction took place (i.e., control experiment without DNA). Both heteroaromatic aldehydes (e.g., 2-pyridinecarboxaldehyde) and aromatic aldehydes bearing strong or moderate electron-withdrawi...

Journal: :Chemical communications 2013
Dongdong Cao Zhuo Chai Jiaxing Zhang Zhengqing Ye Hua Xiao Hongyu Wang Jinhao Chen Xiaoyu Wu Gang Zhao

New chiral bifunctional thiourea-phosphonium salts have been developed based on natural amino acids as highly efficient phase-transfer catalysts in the enantioselective aza-Henry reaction.

Journal: :Green Chemistry Letters and Reviews 2013

An organosuperbase (N,N-dimethylbiguanide) immobilized on mesoporous and magnetically separable silica supports, was found for the first time, to act as a highly-stable, scalable and efficient heterogeneous catalyst for the Henry reaction under mild and neutral condition. Several factors such as catalyst amount, solvent and reaction time concerning the reactivity were also discussed. The proced...

Journal: :Chemical communications 2008
Alexander Adibekian Mattie S M Timmer Pierre Stallforth Jimmy van Rijn Daniel B Werz Peter H Seeberger

A diastereoselective domino nitro-Michael/Henry reaction involving a beta-hydroxyaldehyde and a nitroalkene provides direct access to fully functionalized D-glucosamine monosaccharides.

An organosuperbase (N,N-dimethylbiguanide) immobilized on mesoporous and magnetically separable silica supports, was found for the first time, to act as a highly-stable, scalable and efficient heterogeneous catalyst for the Henry reaction under mild and neutral condition. Several factors such as catalyst amount, solvent and reaction time concerning the reactivity were also discussed. The proced...

Journal: :Chemical communications 2014
Melireth Holmquist Gonzalo Blay José R Pedro

A highly enantioselective aza-Henry reaction with isatin N-Boc ketimines using a Cu(II)-BOX complex as a catalyst is described. The reaction, which does not require protection of the N1 atom, provides the corresponding nitroamines bearing a quaternary stereocentre with high yields and enantiomeric excesses (up to 99.9%).

2018
Tatu Kumpulainen Junhong Qian Albert M. Brouwer

A spectroscopic study of an organocatalytic Henry reaction between nitroalkanes and aldehydes catalyzed by a quinidine-derived Cinchona alkaloid is described. The binding modes of the reaction substrates are investigated using electronic absorption and fluorescence spectroscopy and further corroborated by nuclear magnetic resonance measurements. Aldehydes are shown to associate with both the 6'...

Journal: :Journal of the American Chemical Society 2003
David A Evans Daniel Seidel Magnus Rueping Hon Wai Lam Jared T Shaw C Wade Downey

A highly enantioselective, nitroaldol reaction catalyzed by a chiral Cu(II) bis(oxazoline) complex has been developed. The reaction scope includes both aromatic and aliphatic aldehydes (15 examples) affording products in good yields and enantioselectivities (87-94% ee). An X-ray structure of the catalyst has been provided along with a rationalization of the sense of asymmetric induction.

Journal: :Journal of the American Chemical Society 2005
Claudio Palomo Mikel Oiarbide Antonio Laso Rosa López

In situ generated azomethines from readily available precursors react with nitromethane in the presence of 120 mol % of CsOH.H2O and 12 mol % of quinine- and cinchonidine-derived quaternary ammonium chlorides to provide the corresponding aza-Henry adducts in good yields and very high selectivities. It represents the first general enantioselective aza-Henry method for azomethines derived from en...

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