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Questions tagged [enolate-chemistry]

Enolates are anions derived from the deprotonation of carbonyl compounds. This tag must be used while dealing with the enolates or its derivatives including its resonance forms.

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Why aren't aldehydes more acidic than saturated alcohols?

Aldehydes (pKa ~17-20) and ketones (pKa >20) are worse acids than alcohols (pKa ~15-16). I have seen that the equilibrium of aldehydes (and ketones) with their hydrates greatly decreases pKa values ...
mechanist's user avatar
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Selective formation of enolates

I saw the following reaction on Modern methods of Organic Synthesis by Carruthers. The reaction is about the selective alkylation of trimethylsilyl enolates, and is shown below. However, I have some ...
Cyclopropanol's user avatar
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Mechanism of deprotection of enol thioether

I was reading some enolate chemistry from Carruthers textbook and came across the selective alkylation of unsymmetrical ketones. The reaction involves blocking one alpha-position of the ketone using ...
Cyclopropanol's user avatar
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Reaction mechanism of enolate formation [closed]

In this reaction, KOtBu is supposed to be used to form an enolate first and then ethyliodide is added. I just can't figure out the reaction mechanism of this reaction, can someone help?
roosaveera's user avatar
1 vote
1 answer
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how does enolate affect an elimination reaction?

From my class: But why wouldn't the reaction proceed through this way, which makes more sense? Since the reaction above generates an enolate bearing a negative charge first, making the molecule less ...
HypnoticBuggyWraithVirileBevy's user avatar
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Aldol Cyclization Cascade Reaction between Two Ketones in Basic Alcoholic Solution

My professor gave a hint that the reaction scheme is a multiple carbonyl reaction which involves cyclization. He emphasizes that the reactivity of carbonyl compound in terms of C-H acidity and ...
user4723's user avatar
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stereoselectivity in aldol reactions

in "Advanced Organic Chemistry, part B" fifth edition book, page:103, the authors compare between aldol reactions where 1-substituted nucleophile is used. They stated that when the 1-...
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3 answers
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Nucleophilicity of sterically hindered enolates

Problem Answer Question Here $\ce{KH}$ obviously acts as a base, and forms the enolate from the ketone, which subsequently act as nucleophiles causing an SN2 reaction on the $\ce{CH3I}$. When this ...
TRC's user avatar
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What is the reaction mechanism between acetophenone and ethyl phenylpropiolate to form a 2-pyrone?

I am looking for the mechanism of the following reaction (I believe it is a type of Michael reaction), which is in the textbook "Advanced Organic Chemistry Part B: Reaction and Synthesis" by ...
Richie12138's user avatar
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2 answers
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Acidity of alpha hydrogens in enolate formation

I am interested in why the most right alpha hydrogen is removed to form the carbanion prior to intermolecular aldol condensation (2nd row first molecule). Why is it that the alpha hydrogen from the ...
ImJustKawaii's user avatar
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Which of the following compounds possess more than one percent enol content? [closed]

Which of the following compounds possess more than one percent enol content? I understood that stability of enols are dependent on the hydrogen bonding in the compounds. But here, what is the ...
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Why can't the N- end of the nitrile anion attack the alkyl halide in an SN2 fashion during an alkylation reaction when OH- can?

I'm reading my Clayden textbook and something keeps nagging me. It says that when we're carrying out alkylation reactions with an enol attacking an alkyl halide with strong base catalysis (with ...
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Selectivity in Thermodynamically-Driven Silyl Enol Ether Formation, and Optimistic Avoidance of Protecting Group Chemistry

I am aware of the regioselectivity of silyl enol ether formation at an unsymmetrical ketone under 'thermodynamic conditions'. Does this selectivity extend to systems containing more than one ketone ...
PhenolPhthaleinPurple's user avatar
3 votes
1 answer
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Regioselective enolate formation, choosing major and minor products

This question came in my organic chem assignment. The options highlighted are the answers. The end carbon(adjacent to the carbonyl group) should have more acidic alpha-hydrogen and the alkene formed ...
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Mechanism of acid-catalyzed Robinson annulation?

My professor posed my organic chemistry class a challenge problem for bonus points and I've been racking my brain over the last three days trying to work it out and I want to know if my solution is ...
Chris Sullivan's user avatar
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how is the esterification of amino acid carried on in this reaction

i was asked to synthesis this compound from this amino acid, i first alkylated the alpha carbon using enolate alkylating method then i esterficated the amino acid but i'm doubtful that my steps are ...
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Help with mechanism similar to Robinson Annulation

I need to figure out a mechanism for this reaction. All I know is that it is supposed to have a similar mechanism to Robinson Annulation. This is the best I could come up with, but I've been told it ...
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Grignard reagent will act as a base or a nucleophile [duplicate]

R- from grignard reagent (RMgBr) and gilmann's reagent (R2CuLi) although being a strong base reduces the carbonyl group and does not act as a base. Why can't it abstract the alpha hydrogen forming an ...
Yashwini's user avatar
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How would I synthesize ethyl 2‐oxocyclohexane‐1‐carboxylate from cyclohexanone? [closed]

I thought the 1st step would be deprotonation of a H atom to form the enolate. Then an aldol reaction, but the product I end up with is the alcohol, not the ketone.
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2 votes
1 answer
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Can R-3-methyl-4-heptanone be enantioselectively synthesised from 4-heptanone?

I wonder if it is possible to do the following reaction with its enantioselectivity: I am trying to do it via enolate, but I don't know how to make only the R product or if it's even possible to ...
Miguel Ángel Rodríguez VIdal's user avatar
4 votes
1 answer
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Role of NaI in Formation of Silyl Enol Ethers using Chloro(trimethyl)silane

I am forming silyl enol ethers using Chloro(trimethyl)silane (TMSCl), and below is an experimental protocol I am following Silyl Enol Ether Synthesis In an oven-dried 100 mL three-necked ...
chemrese's user avatar
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Enolate ion opening an epoxide?

Does anyone know if it is possible to open an epoxide and do a 2-C extension using an enolate ion, say, of acetone? Here's an example of what I mean: Based on what I know of enolate chemistry, this ...
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Alkylation of acetophenone

When the NaOH deprotonates the hydrogen off the carbon, I thought there would be a resonance structure, with the negative charge being on both the oxygen and carbon. Since the oxygen is more stable ...
anon3333's user avatar
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2 answers
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Less substituted vs more substituted alkene [closed]

In general, more substituted alkenes are more thermodynamically stable. However, in certain cases such as enamine alkylation, the less substituted double bond is favored. How do we know that which is ...
Science123's user avatar
3 votes
1 answer
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How does base size affect the ratio of kinetic/thermodynamic enolate?

One of the factors that favor kinetic products is bulky bases. So, I'd expect that, for a certain substrate, the use of a more bulky base to favor even more the kinetic product. However, in the table ...
Αντώνιος Κελεσίδης's user avatar
3 votes
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281 views

Claisen-like condensation with acid chloride

In the Claisen condensation, an ester enolate attacks an ester, with an alkoxide anion leaving subsequently to give a $\beta$-keto ester. Is it possible for a typical enolate of an aldehyde or ketone ...
Tan Yong Boon's user avatar
5 votes
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Increasing C-alkoxycarbonylation of enolates

I am working with N-tosyl-2-piperidone and attempts to use the lithium enolate of this compound to perform an nucleophilic acyl substitution reaction on an several chloroformate esters in THF has lead ...
SendersReagent's user avatar
2 votes
0 answers
173 views

Does the amine used to generate the enolate affect the selectivity of an Evans aldol reaction?

In an Evans aldol reaction, the enolate is typically generated by addition of a boron Lewis acid (e.g. $\ce{(n-Bu)2BOTf}$) and an amine, which acts as a weak base. I'd like to know whether there's any ...
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