Search results for "catalytic hydrogenation"
showing 6 items of 6 documents
The history and future challenges associated with the hydrogenation of vinyl fluorides
2018
Abstract Catalytic hydrogenation is one of the most powerful transformations available in synthetic chemistry; there have been three Nobel Laureates rewarded for their work in the field. Despite the advances in substrate scope and the development of enantioselective versions of this transformation, vinyl fluorides remain somewhat underrepresented. Successful hydrogenation of vinyl fluorides can give rise to a fluorine-containing stereocenter, an important feature which has great potential in many areas of chemistry. This review aims to explore the history of vinyl fluorides as substrates in hydrogenation reactions, and to highlight modern day challenges and unresolved issues regarding this …
Synthese und Eigenschaften molekulareinheitlicher n-Paraffine bis zum C140H282
1972
Die Umsetzung von α,ω-Dihalogenalkanen mit Natrium fuhrt nach anschliesender katalytischer Hydrierung zu einem Paraffingemisch mit diskontinuierlicher Molekulargewichtsverteilung. So enthalt das aus 1.10-Dibromdecan hergestellte Produkt nur Paraffine mit 10, 20, 30 usw. C-Atomen, ein aus 1.20-Dibromeicosan hergestelltes Produkt dagegen nur die Paraffine mit 20, 40, 60 usw. C-Atomen. Diese Paraffingemische wurden gelchromatographisch in die molekulareinheitlichen Verbindungen zerlegt und Paraffine bis C140H282 isoliert. Am Beispiel des C70H142 wurde die Temperaturabhangigkeit der Rontgenkleinwinkelstreuung gemessen. Aus Intensitat und Lage der Langperiodenreflexe liesen sich die Anderungen v…
Functionalized 2-azabicyclo[3.3.1]nonanes. IV. synthesis of the indolo[3,2-f]morphan system.
1982
Abstract A short route to the 2-azabicyclo[3.3.1]nonan-7-one system is described. Condensation of 4-piperidones with diethyl 2-oxopropylphosphonate, followed by catalytic hydrogenation furnished the corresponding piperidylpropanones 6 which were cyclized with mercuric acetate in acetic acid to the target target bicyclic ketones 1 . The Fischer indole synthesis from 1 a afforded regioselectively the indole [3,2-f]morphan 2 , a new heteromorphan type.
Atomically Precise, Thiolated Copper–Hydride Nanoclusters as Single-Site Hydrogenation Catalysts for Ketones in Mild Conditions
2019
Copper-hydrides are known catalysts for several technologically important reactions such as hydrogenation of CO, hydroamination of alkenes and alkynes, and chemoselective hydrogenation of unsaturated ketones to unsaturated alcohols. Stabilizing copper-based particles by ligand chemistry to nanometer scale is an appealing route to make active catalysts with optimized material economy; however, it has been long believed that the ligand-metal interface, particularly if sulfur-containing thiols are used as stabilizing agent, may poison the catalyst. We report here a discovery of an ambient-stable thiolate-protected copper-hydride nanocluster [Cu25H10(SPhCl2)18]3- that readily catalyzes hydrogen…
Theoretical evaluation of structures and energetics involved in the hydrogenation of hydrocarbons on palladium surfaces
2001
Abstract Quantum mechanical calculations were employed to deepen information about the basic properties of the mechanism occurring in the palladium catalytic hydrogenation involving surface hydrogen species of unsaturated hydrocarbons. Activation energy values of elementary events implicated in the whole reaction were computed by potential energy surface analyses, to determine the corresponding occurrence probabilities of the same events. Different surface hydrogen species were pointed out and their relevance in the overall surface process was discussed together with their geometrical and chemical characteristics.
Über die auslösung der polymerisation ungesättigter verbindungen durch aktivierten wasserstoff
1953
In Ubereinstimmung mit Wilson und Parravano wurde gefunden, das Methacrylsauremethylester, Acrylnitril, Acrylsaure und Acrylsauremethylester in wasriger Losung durch an der Kathode abgeschiedenen Wasserstoff polymerisiert werden. Die Reibenfolge der Wirksamkeit des Kathodenmaterials entspricht derjenigen der elektrolytischen Reduktion und der Uberspannungsreihe. Die Kathodische Polymerisation verlauft uber Radikale; sie kann durch molekularen Sauerstoff inhibiert werden. - Katalytisch erregter Wasserstoff (Pd-Katalysator) kann als Reduktionsmittel von Redoxsystemen Polymerisation von Acrylnitril und anderen Monomeren auslosen. Unter bestimmten Bedingungen erfolgen katalytische Hydrierung un…