نتایج جستجو برای: asymmetric catalyst

تعداد نتایج: 108514  

Journal: :Chemical science 2017
Hong-Gang Cheng Javier Miguélez Hiroyuki Miyamura Woo-Jin Yoo Shū Kobayashi

A new class of chiral bifunctional heterogeneous materials composed of Au/Pd nanoparticles and chiral phosphoric acids as active orthogonal catalysts was prepared by utilizing a facile pseudo-suspension co-polymerization method. It was found that this heterogeneous catalyst was capable of facilitating the sequential aerobic oxidation-asymmetric intramolecular aza-Friedel-Crafts reaction between...

2017
Hong-Gang Cheng Javier Miguélez Hiroyuki Miyamura Woo-Jin Yoo Shū Kobayashi

A new class of chiral bifunctional heterogeneous materials composed of Au/Pd nanoparticles and chiral phosphoric acids as active orthogonal catalysts was prepared by utilizing a facile pseudo-suspension copolymerization method. It was found that this heterogeneous catalyst was capable of facilitating the sequential aerobic oxidation-asymmetric intramolecular aza-Friedel–Crafts reaction between ...

Journal: :Angewandte Chemie 2014
Wenjun Zhao Li Huang Yong Guan William D Wulff

The first chiral catalyst for the three-component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH3·SMe2, and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8-...

Journal: :Organic & biomolecular chemistry 2011
Feng Yu Xi-Chang Zhang Fei-Fei Wu Ji-Ning Zhou Wenjun Fang Jing Wu Albert S C Chan

In the presence of PhSiH(3) as the hydride donor, catalytic amounts of non-racemic dipyridylphosphine and an easy-to-handle cobalt salt Co(OAc)(2)·4H(2)O formed in situ an effective catalyst system for the asymmetric reduction of a diverse range of aryl alkyl ketones with moderate-to-excellent enantioselectivities (up to 96% ee). This approach tolerated the handling of both catalyst and reactan...

Journal: :Journal of the American Chemical Society 2009
Vincent S Chan Melanie Chiu Robert G Bergman F Dean Toste

This work details the development of ruthenium(II) catalysts for the enantioselective alkylation of chiral racemic secondary phosphines. The reactions proceed through the intermediacy of nucleophilic phosphido species, which have low barriers to pyramidal inversion; this allows for a dynamic kinetic asymmetric alkylation. The initially discovered [((R)-iPr-PHOX)(2)Ru(H)][BPh(4)] (6) catalyst wa...

Journal: :Chemical communications 2007
Li Zhou Zhouyu Wang Siyu Wei Jian Sun

L-Pipecolinic acid derived Lewis basic N-formamide has been developed as a first highly effective catalyst for the asymmetric reduction of aromatic and aliphatic ketones as well as aromatic and aliphatic ketimines in good to high enantioselectivity.

Journal: :Organic & biomolecular chemistry 2016
Bo-Xu Feng Bin Wang Xin Li

A highly enantioselective asymmetric addition reaction of thioglycolates and N-Boc aldimines was promoted by a bifunctional tertiary-amine squaramide catalyst. As a result, a number of chiral N,S-acetal derivatives were efficiently synthesized with good enantioselectivities.

Journal: :Molecules 2012
Seung-Mann Paek

Fully substituted olefin generation via metathesis is presented. Catalyst development, optimization of reaction conditions and substrate screening are included. In addition, asymmetric alkene metathesis, the cross metathesis reaction for this transformation and its application in natural products will be discussed.

Journal: :Organic & biomolecular chemistry 2015
Chaoyuan Zeng Fan Yang Jingchao Chen Jun Wang Baomin Fan

A combination of iridium/copper associated with (R)-Difluorphos catalyst for the asymmetric ring opening reaction of azabenzonorbornadienes with amines was developed, which afforded chiral trans-vicinal diamines in 80-97% yields with 93-95% enantioselectivities.

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