نتایج جستجو برای: hydrogenation
تعداد نتایج: 8711 فیلتر نتایج به سال:
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.
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...
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 ...
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...
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...
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 ...
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.
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...
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 ...
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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