نتایج جستجو برای: asymmetric catalysis

تعداد نتایج: 90956  

Journal: :European Journal of Organic Chemistry 2023

Phase Transfer Catalysis (PTC) is a powerful tool to perform reactions in practical fashion, both laboratory and industrial scale. Significant cost savings major process improvements can be achieved performed under PTC conditions. In the last few years remarkable results stereoselective were using chiral, non-racemic quaternary ammonium salts. Moreover, use of bulky, chiral phosphate anions pai...

Journal: :Chemical communications 2008
Khalid B Selim Ken-ichi Yamada Kiyoshi Tomioka

Phenyl- and ethyl-magnesium bromides undergo regioselective asymmetric allylic substitution with high enantioselectivity under the catalysis of chiral amidophosphane-copper(I) complexes.

Journal: :Organic & biomolecular chemistry 2011
Jadwiga Gajewy Jacek Gawronski Marcin Kwit

Chiral hexamine macrocycle derived from trans-1,2-diaminocyclohexane (DACH) in a complex with diethylzinc efficiently catalyzes the asymmetric hydrosilylation of N-phosphorylated aryl-alkyl or aryl-aryl ketimines in protic media with enantiomeric excess of the product approaching 100%. The cyclic structure of the trianglamine ligand increases the enantioselectivity and/or the yield of the react...

Journal: :Chemical communications 2015
Erica Benedetti Nicolas Duchemin Lucas Bethge Stefan Vonhoff Sven Klussmann Jean-Jacques Vasseur Janine Cossy Michael Smietana Stellios Arseniyadis

The challenge in DNA-based asymmetric catalysis is to perform a reaction in the vicinity of the helix by incorporating a small-molecule catalyst anchored to the DNA in a covalent, dative, or non-covalent yet stable fashion in order to ensure high levels of enantio-discrimination. Here, we report the first generation of a DNA-based catalyst bound to a cellulose matrix. The chiral biomaterial is ...

Journal: :Nature communications 2016
Ji-Wei Zhang Jin-Hui Xu Dao-Juan Cheng Chuan Shi Xin-Yuan Liu Bin Tan

Axially chiral compounds play an important role in areas such as asymmetric catalysis. The tyrosine click-like reaction is an efficient approach for synthesis of urazoles with potential applications in pharmaceutical and asymmetric catalysis. Here we discover a class of urazole with axial chirality by restricted rotation around an N-Ar bond. By using bifunctional organocatalyst, we successfully...

Journal: :Chemical communications 2012
Dhevalapally B Ramachary Chintalapudi Venkaiah Patoju Murali Krishna

We present herein for the first time the asymmetric synthesis of drug-like spiranes through reflexive-Michael reaction by using 2-aminobuta-1,3-enyne catalysis under mild conditions.

Journal: :Organic & biomolecular chemistry 2010
Masanori Yoshida Atsushi Sato Shoji Hara

Enantioselective Michael addition of aldehydes to nitroalkenes was successfully carried out by asymmetric catalysis with L-phenylalanine lithium salt, giving gamma-nitroaldehydes in good yields with high enantioselectivity.

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