Alpha Hydrogen Acidity
Alpha Hydrogen Acidity - Related Videos
06:06
Hydrogenation
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2023
Source: Vy M. Dong and Zhiwei Chen, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the hydrogenation of chalcone as an example of an alkene hydrogenation reaction (Figure 1). In this experiment, palladium on carbon (Pd/C) will be used as a heterogeneous catalyst for the process. A balloon will be used to supply the hydrogen atmosphere. Figure 1: Diagram showing the hydrogenation of chalcone to 3-phenylpropiophenone.
09:51
Measuring Plant Cell Wall Extension (Creep) Induced by Acidic pH and by Alpha-Expansin
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Cited by 43 •
2009
We demonstrate the use of a constant-force extensometer to measure long-term extension (creep) of plant cell wall specimens induced by acidic buffers and expansin protein.
08:21
Curation of Computational Chemical Libraries Demonstrated with Alpha-Amino Acids
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Cited by 2 •
2022
The purpose of this protocol is to efficiently generate and curate small-molecule structure libraries using open-source software.
08:40
Millisecond Hydrogen/Deuterium-Exchange Mass Spectrometry for the Study of Alpha-Synuclein Structural Dynamics Under Physiological Conditions
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Cited by 8 •
2022
The structural ensemble of monomeric alpha-synuclein affects its physiological function and physicochemical properties. The present protocol describes how to perform millisecond hydrogen/deuterium-exchange mass spectrometry and subsequent data analyses to determine conformational information on the monomer of this intrinsically disordered protein under physiological conditions.
08:56
Catalytic Reactor: Hydrogenation of Ethylene
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2023
Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA The hydrogenation of ethylene (C2H4) to ethane (C2H6) has often been studied as a model reduction reaction in characterizing new metal catalysts.1-2 While supported nickel is not the most active metal catalyst for this reaction, it is active enough that reaction can take place at < 200°C. The reaction typically involves adsorbed, dissociated hydrogen (H2) reacting...
FAQs
Resonance stabilizes the enolate produced after deprotonation by distributing negative charge between the alpha carbon and the carbonyl oxygen. This delocalization lowers the energetic cost of forming the reactive species and explains why carbonyl compounds can participate in subsequent transformations. The resulting enolate provides a mechanistic basis for predicting reactivity rather than treating proton removal as an isolated event.
Electron-withdrawing substituents increase alpha hydrogen acidity by providing additional stabilization for the negatively charged enolate. Their influence works alongside resonance involving the carbonyl group, so the combined stabilization helps explain differences in how readily related carbonyl compounds undergo deprotonation. Considering these substituents is therefore important when assessing whether enolate formation is plausible in a proposed reaction.
Alpha hydrogen acidity helps explain why carbonyl compounds can exist through keto-enol tautomerism. Removal of an alpha proton creates an enolate, and changes involving that intermediate can support formation of the corresponding enol arrangement. Recognizing this relationship allows chemists to connect proton-transfer behavior with the interconversion of carbonyl-containing structures during mechanistic analysis.
Comparison should begin by locating the carbon next to the carbonyl and determining whether it bears hydrogen that can be removed. The analysis then considers enolate stabilization through resonance and any additional electron-withdrawing substituents. This approach applies across aldehydes, ketones, esters, and related compounds without relying only on the carbonyl compound's name or classification.
A practical analysis starts by identifying an alpha hydrogen, predicting the enolate formed after deprotonation, and assessing how resonance or electron-withdrawing substituents stabilize it. The proposed enolate can then be evaluated for carbon-carbon bond formation through alkylation, aldol reactions, or related condensations. This workflow connects structural analysis with deliberate organic synthesis planning.
It indicates whether a carbonyl compound can generate an enolate and therefore participate in transformations that extend its carbon framework. In reaction interpretation, the concept links the starting structure to enolate formation, carbon-carbon bond construction, and possible condensation behavior. It is especially useful for explaining why a carbonyl compound follows a particular synthetic pathway rather than merely identifying its functional group.