Basenbildung aus Carbonylverbindungen

Skita, A.; Keil, Frerich J.

doi:10.1002/cber.19280610706

Cited by 24 publications

(12 citation statements)

References 7 publications

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“…142 One year later, Skita and Keil published the amination of aldehydes and ketones with aqueous NH 3 using the same colloidal Pt solution as a catalyst (Scheme 74B). 143 Highermolecular-weight aldehydes (citral and heptanal) led to the formation of secondary amines, while the use of lowermolecular-weight aldehydes (acetaldehyde and propionaldehyde) led to the formation of tertiary amines. Furthermore, ketones could be successfully transformed to the corresponding secondary amines using aqueous NH 3 .…”

Section: Reductive Amination Using Heteregeneous Transition Metal Cat...mentioning

confidence: 99%

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

2020

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The reductive amination, the reaction of an aldehyde or a ketone with ammonia or an amine in the presence of a reducing agent and often a catalyst, is an important amine synthesis and has been intensively investigated in academia and industry for a century. Besides aldehydes, ketones, or amines, starting materials have been used that can be converted into an aldehyde or ketone (for instance, carboxylic acids or organic carbonate or nitriles) or into an amine (for instance, a nitro compound) in the presence of the same reducing agent and catalyst. Mechanistically, the reaction starts with a condensation step during which the carbonyl compound reacts with ammonia or an amine, forming the corresponding imine followed by the reduction of the imine to the alkyl amine product. Many of these reduction steps require the presence of a catalyst to activate the reducing agent. The reductive amination is impressive with regard to the product scope since primary, secondary, and tertiary alkyl amines are accessible and hydrogen is the most attractive reducing agent, especially if large-scale product formation is an issue, since hydrogen is inexpensive and abundantly available. Alkyl amines are intensively produced and use fine and bulk chemicals. They are key functional groups in many pharmaceuticals, agro chemicals, or materials. In this review, we summarize the work published on reductive amination employing hydrogen as the reducing agent. No comprehensive review focusing on this subject has been published since 1948, albeit many interesting summaries dealing with one or the other aspect of reductive amination have appeared. Impressive progress in using catalysts based on earth-abundant metals, especially nanostructured heterogeneous catalysts, has been made during the early development of the field and in recent years.

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Section: Reductive Amination Using Heteregeneous Transition Metal Cat...mentioning

confidence: 99%

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

2020

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“…Similarly, the yield of secondary amine in the reaction between acetone, methyl ethyl ketone or diethyl ketone and cyclohexylamine decreased with increasing steric hindrance around the carbonyl function. [29] Steric hindrance plays also a role around the amine function. For example, reductive amination of acetone with 2,4,6-trimethylaniline afforded the secondary amine, N-isopropyl-2,4,6-trimethylaniline, in only 36% yield while, with aniline, the yield of the corresponding secondary amine was 98% (Scheme 10).…”

Section: Steric Effectsmentioning

confidence: 99%

The Reductive Amination of Aldehydes and Ketones and the Hydrogenation of Nitriles: Mechanistic Aspects and Selectivity Control

Gomez

Peters

Maschmeyer

2002

Advanced Synthesis & Catalysis

523

238

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This review deals with two of the most commonly used methods for the preparation of amines: the reductive amination of aldehydes and ketones and the hydrogenation of nitriles. There is a great similarity between these two methods, since both have the imine as intermediate. However, due to the high reactivity of this intermediate, primary, secondary and/or tertiary amines are obtained (often simultaneously). The relation of the selectivity to different substrate structures and reaction conditions is briefly summarised, the main focus being on the catalyst as it is the most significant factor that governs the selectivity. Different mechanisms are discussed with the view to correlate the structure of the catalyst and, more particularly, the nature of the metal and the support with selectivity. The crucial point is the presumed location of the condensation and hydrogenation steps.

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“…[ 163 ] Triethylamine was prepared by reaction of ammonia and acetaldehyde with hydrogen. [ 126,164 ]…”

Section: Trialkylamines Synthesismentioning

confidence: 99%

“…[163] Triethylamine was prepared by reaction of ammonia and acetaldehyde with hydrogen. [126,164] In 2005 Ishii and co-authors developed an iridium-catalyzed reductive amination using hydrosilanes as a reducing agents and applied it for the nBu 3 N synthesis. [165] [Ir(cod)Cl] 2 and IrCl 3 were shown to be active catalysts in this reaction with [Ir(cod)Cl] 2 allowing to use a little bit milder conditions in comparison with IrCl 3 .…”

Section: Classical Reductive Amination Of Aldehydes and Ketonesmentioning

confidence: 99%