نتایج جستجو برای: hydrogenation

تعداد نتایج: 8711  

Journal: :Organic & biomolecular chemistry 2015
Grzegorz Krzysztof Zieliński Cezary Samojłowicz Tomasz Wdowik Karol Grela

A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity.

Journal: :Angewandte Chemie 2007
Magnus Rueping Andrey P Antonchick

Asymmetric hydrogenation is one of the most important enantioselective reactions. Although the hydrogenation, transfer hydrogenation, and hydrosilylation of various substrates in the presence of metal catalysts have been described, the asymmetric reduction of aromatic and heteroaromatic compounds still represents a great challenge. This situation is particularly true for the enantioselective hy...

Journal: :Physical chemistry chemical physics : PCCP 2015
Yongjie Xi Zhangxian Chen Vincent Gan Wei Kiat Liang Huang Hansong Cheng

Hydrogenation of unsaturated organosulfur compounds is an essential process through which these species are converted into cleaner and more useful compounds. Hydrogen bronze materials have been demonstrated to be efficient catalysts in hydrogenation of simple unsaturated compounds. Herein, we performed density functional theory calculations to investigate hydrogenation of thiophene on hydrogen ...

Journal: :Chemical science 2015
Zhang-Pei Chen Mu-Wang Chen Lei Shi Chang-Bin Yu Yong-Gui Zhou

An efficient palladium-catalyzed asymmetric hydrogenation of fluorinated aromatic pyrazol-5-ols has been developed via capture of the active tautomers. A wide variety of 2,5-disubstituted and 2,4,5-trisubstituted pyrazolidinones have been synthesized with up to 96% and 95% ee, respectively. The hydrogenation pathway includes Brønsted acid promoted tautomerization of pyrazol-5-ols and Pd-catalyz...

2018
Feng Li Jinrong Liang Wenxi Zhu Hua Song Keliang Wang Cuiqin Li

In-situ liquid-phase hydrogenation of m-chloronitrobenzene (m-CNB) based on aqueous-phase reforming (APR) of ethanol and catalytic hydrogenation was carried out over Fe-modified Pt/carbon nanotubes (CNTs) catalysts. The effects of Pt loading over CNTs and Fe modification on the catalytic performance of Pt/CNTs catalysts were studied. In-tube loading of Pt particles, compared with out-tube loadi...

2008
Tamara L. Church Pher G. Andersson

Chiral iridium catalysts have now been used in the asymmetric hydrogenation of largely unfunctionalized olefins for a decade. Recently, they have also been applied to substrates with more exotic functional groups, including non-coordinating ones. These, unlike coordinating substituents, cannot direct asymmetric hydrogenation by rhodiumor ruthenium-based catalysts. This review discusses several ...

2017
Sunil B. Shinde Raj M. Deshpande

Hydrogenation of benzoic acid using monoand bimetallic catalyst of Ru, Pd, Co, and Re yielded different products. It was observed that 5% Ru/C was an active catalyst for hydrogenation of both aromatic ring and carboxylic group, while Pd/C catalyst hydrogenated only aromatic ring. Ru-Sn/Al2O3 is a chemoselective catalyst for hydrogenation of –COOH group of benzoic acid.

2009
Yichen Tan

INTRODUCTION Asymmetric hydrogenation of unsaturated organic compounds has been established as one of the most efficient methods for the preparation of chiral, non-racemic substrates. Among hydrogenation of various substrates, the asymmetric hydrogenation of heteroarenes provides a straightforward approach to a wide range of enantiomerically pure saturated heterocycles, which are subunits of ma...

Journal: :Angewandte Chemie 2002
Ai-Guo Hu Yu Fu Jian-Hua Xie Hai Zhou Li-Xin Wang Qi-Lin Zhou

Optically active -arylalkylamines are an important class of compounds that are widely used in organic and pharmaceutical synthesis, and much effort has been made to develop efficient asymmetric synthetic methods for them.[1] Asymmetric catalytic hydrogenation of enamides, initiated by Kagan et al. ,[2] provides a direct and convenient route to chiral amine derivatives. However, many well-known ...

Journal: :Nanoscale 2015
Amr M Abdelkader Hollie V Patten Zheling Li Yiqiang Chen Ian A Kinloch

We demonstrate a facile and scalable electrochemical approach to exfoliate graphite, which permits in situ hydrogenation of the resultant graphene via a solvated NR(4+) graphite compound in quaternary ammonium-based deep eutectic solvents. Spectroscopic studies reveal the presence of sp(3) C-H bonds in the hydrogenated graphene. The resulting materials consist of micrometre-sized and predominan...

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