Questions tagged [carbonyl-compounds]

For questions about compounds containing the carbonyl group, C=O, the carboxylic acid group (-COOH), or its derivatives (anhydrides/esters/amides/acid halides). For questions about complexes involving carbon monoxide as a ligand use [carbonyl-complexes] instead.

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Why are carbonyl groups so important [closed]

The most important are π orbitals as they are lower in energy than σ orbitals and the carbonyl group (C=O) is the most important of these—indeed it is the most important functional group of all. ~...
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Difference between base-promoted and base-catalysed

Why is halogenation of ketones in base described as being "base-promoted" and not "base-catalysed"? If the reaction is not "catalyzed" then how is the base used up?
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Why do carbonyl compounds undergo nucleophilic and not electrophilic addition?

Why aldehydes and ketones undergo nucleophilic addition reactions and not electrophilic addition? Alkenes show electrophilic addition because of pi bond, which is also present in aldehydes and ...
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What causes the blackening of light bulbs

in 1878, Thomas Edison (or rather William Joseph Hammer) added an anode in a light bulb in order to catch the flux of electrons coming out from the carbon filament and reduce the phenomenon of ...
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1answer
107 views

Grignard alkene on a carbonyl

I was given the following mechanism to prove today post-lecture: and my attempt is given below. Now, when the negative charge on the alkene attacks the carbonyl, the electrons are pushed onto the ...
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2answers
769 views

Reaction of coumarin with phenylmagnesium bromide

I came across this problem.. I thought that the Grignard reagent, PhMgBr, would cleave the lactone and then subsequently add to the ketone formed, giving an allylic tertiary alcohol after aqueous ...
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83 views

Acidity order of carboxylic compounds [duplicate]

Arrange the following acids in decreasing order of acidity: (a) X > Z > Y (b) X > Y > Z (c) Z > X > Y (d) Z > Y > X I arrived at option (c) according to -I effect, but the answer ...
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3answers
364 views

What is the keto form of a hexahydroxybenzene?

159. The keto isomer of the following compound is: The answer has been given as (c). I cannot seem to understand why is it not possible for the keto form to only have one OH convert into keto ...
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777 views

Decarboxylation mechanism and stability of α,β-unsaturated and α-hydroxy acids

I was wondering why α,β-unsaturated and α-hydroxy acids undergo decarboxylation. Also, I'm aware of neither the products nor mechanism. All I know is that β-keto acids and α-nitro compounds have ...
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1answer
939 views

Why does aceto acetic ester not respond to haloform test even though it has a keto methyl group? [closed]

Why does aceto acetic ester not respond to haloform test even though it has a keto methyl group?
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62 views

Aldol Reaction in Water Not Working

I am conducting an Aldol formation reaction in water, and below is the experimental protocol I am following (from J. Org. Chem. 1994, 59, 3590—3596): Formation of Aldol in Water using Yb(OTf)3 ...
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2answers
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Haloform reaction with limited bromine

We were asked the reaction between 1 mole acetone and 1 mole $\ce{Br2}$ in basic medium. Since only a limited amount of bromine was given I got the final answer as 1-bromopropan-2-one (mono bromo ...
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142 views

1,4-addition vs 1,2-addition aldol/aldol type reactions

In the aldol/cross aldol reaction, of $α,β$-unsaturated carbonyl compound, under what circumstances does a 1,2-addition i.e. aldol condensation (carbanion formed directly attacking carbon of carbonyl ...
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2answers
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Mechanism of a cyclization reaction - why does an enol ether form?

I was asked to predict compound A from the follwing organic scheme: Looking at the formation of A, my prediction was that since TsOH is a strong acid, it would dehydrate the alcohols (like sulfuric ...
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2answers
467 views

Synthetic steps for the interconversion between aldehydes and ketones

I am learning about carbonyl chemistry at the moment. So far, we have been able to make aldehydes and ketones from alcohols (via oxidizing agents). I can't help but wonder if there is possibly any way ...
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3answers
845 views

Reaction of NaOD/D2O with semicarbazone

I managed to solve the question till D but I'm stuck at the last reaction. I tried to find its solution and the source suggest it as
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1answer
5k views

Why do alpha-hydroxy ketones respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests?

I learnt from a certain textbook that aldehydes and formic acid respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests. However, in another textbook I read that even alpha-...
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1answer
3k views

Best reagent for reducing a ketone in the presence of an alkene

The following reduction is best accomplished with: (a) Zn/Hg, conc. HCl (b) N2H4, C2H5ONa (c) H2, Pd (d) All of the above My thoughts: By looking at the question it is evident that ...
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99 views

Reagents for synthesis of ethyl 2-(2,3-dihydrobenzofuran-2-yl)acetate from naphthalen-1(4H)-one

The following conversion can be performed in a few steps. Show key intermediates and reagents (detailed mechanisms are not required). So I've been looking at this for a while and I can't seem ...
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341 views

Can 1,3,5-trihydroxybenzene perform haloform reaction?

As far as I know it's not possible for 1,3,5-trihydroxybenzene to give the haloform reaction. The prerequisites(that I know) for the haloform reaction are: Only those organic compounds which can be ...
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1answer
362 views

Dehydration of carboxylic acids with phosphoric acid

To find Z one must find X. Finding Y is of no use to find Z. I get X as: After addition of $\ce{H2/Pd-C}$, the unsaturated portion becomes saturated and the carboxylic acid remains unchanged. ...
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1answer
88 views

Why only ketone forms enolate in Claisen condensation between ester and ketone?

Claisen condensation involves nucleophilic substitution in esters by an enolate (formed by removing an alpha-H from an ester or a ketone) giving a beta-keto ester or a diketone. My textbook says ...
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1answer
732 views

Naming ester as a substituent to carboxylic acid

Can carboxylic acid functional group -COOH and ester's functional group R-COO-R' be in one structure? If yes, carboxylic acid will be the parent chain and ester will be the substituent as c.a. is ...
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1answer
887 views

Predict the major product of the following reaction with mechanism [closed]

I started to do the problem by coordinating H+ with the lone pair of oxygen then after that I can't proceed .please send the solution by show the detailed mechanism.
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1answer
321 views

Which one is the stronger base?

I'm studying Wolff-Kishner reduction and I don't understand why after this step the leaving group is $\ce{OH-}$ instead of $\ce{^-HN-NH2}$. I guess it's because hydroxide ion is less strong than the ...
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63 views

An unconventional decarboxylation to form bullatenone

I recently had an assessment which required me to draw the mechanism of decarboxylation of a $\beta$-ketoacid. However, it is slightly peculiar because there is the presence of $\alpha$, $\beta$-...
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158 views

Reaction of Br2/KOH with succinic anhydride

What products will be formed when $\ce{Br2/KOH}$ reacts with the following compound in water at room temperature? Here is what I think is possible: $\ce{OH-}$ will take up the acidic hydrogen. ...
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81 views

Rate of nucleophilic addition reaction of carbonyl compounds

How should I compare the order of rate of 1.formaldehyde 2.ethanal 3.p-nitrobenzaldehyde 4.p-methoxybenzaldehyde For nucleophilic addition the rate depends on the intensity of electron deficiency of ...
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4answers
6k views

Why do Organolithium or Grignard reagents act as nucleophiles and not as bases with aldehydes and ketones

I've read entire Chapter 14: Organometallic Compounds of Francis Carey's "Organic Chemistry" but I still didn't get an answer to my question. Quote from the book: Because of their basicity ...
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1answer
73 views

What happens in this reaction! Some hints needed

I understand step A involves reductive ozonolysis. and that step B is addition involves addition of ammonia to the carbonyl site to form imines. But what does the sodium salt of trichloroacetic acid ...
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1answer
118 views

Why does the carbonyl of carboxylic acids get protonated and not the hydroxyl group?

Is the O of the C=O group more electronegative or is it for the sake of getting from product A to B that the carbonyl is protonated rather than the hydroxyl?
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Ring contraction in benzilic rearrangement

Wikipedia says that, Benzilic acid rearrangement occurs with ring contraction when used on cyclic diketones. But gave no explanation, can you please elaborate on this with some mechanism. One ...
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303 views

Ketal formation of ethyl acetoacetate

Why does the ketone carbonyl group react in preference to the ester carbonyl? Is it something to do with the resonance occurring into the ester carbonyl from the oxygen? but how does this make the ...
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4answers
2k views

Reasons for negative iodoform test

Why does 2',6'-dimethylacetophenone not give iodoform test?
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130 views

Mechanism for formation of amides from ammonium carboxylate salts

One of the reactions that you can do with a carboxylic acid is to react it with ammonia or an amine, which produces the corresponding ammonium carboxylate salt. When this salt is heated, amide is ...
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220 views

Why don't acyl chlorides give positive test with 2,4-DNPH?

In this post, Ron discusses the reasons why carboxylic acid derivatives such as amides, acids and esters do not give a positive result with 2,4-dinitrophenylhydrazine. He mentions that it is largely ...
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1answer
167 views

What reaction takes place here? [duplicate]

Upon reading the given question, I realized that: The first reaction is an aldol condensation reaction between the given compound and formaldehyde. So the product after 1st step is: Now, the ...
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1answer
125 views

Reaction of diacetyl with acid

What happens when diacetyl, that is, butan-2,3-dione is treated with acid? I guess there would be acid catalysed aldol formation. But what would the final product be? I can see too many ...
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1answer
142 views

Carbonation of Grignard reagent with a carbonyl group present in it

Here's the question in my book (see picture) Option A is a standard reaction which gives a carboxylic acid. Option B is definitely wrong because an acid base reaction will take place and CH4 will be ...
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How does chelation control result in rate acceleration?

In the chapter on diastereoselectivity in Clayden, Warren & Greeves (2012), the Cram-Chelate model is discussed. Most significantly, under chelation control, the diastereoselectivity of the ...
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Reactivity of formaldehyde and 2-chloroethanal towards nucleophillic addition

Formaldehyde is sterically less hindered than 2-chloroethanal and inductiv effects also support a greater reactivity of formaldehyde over the later. However my textbook states that the reactivity ...
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1answer
231 views

Reduction with NH2-NH2 , OH-, and glycol

this question was asked in my exam and I have done it properly until the very third step but unfortunately, although the last step looked like wolfkishner reduction to me I could not do it. My ...
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1answer
942 views

How can benzaldehyde have a pKa of 14.9?

There are numerous websites out there which claim that the pKa of benzaldehyde – C6H5CHO – is 14.90. (Just do a Google search for benzaldehyde pka to see what I ...
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The use of silyl enol ethers over aza-enolates

I do not quite understand how alkylations using tertiary halides would work better with silyl enol ethers, compared with using the aza-enolate nucleophile. The following was mentioned in Clayden, ...
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1answer
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Is butanoic acid more soluble in water than ethyl acetate?

I was asked which of the two following isomeric compounds, a carboxylic acid and an ester, was more soluble in water. I believe both molecules should be somewhat soluble in water as they have polar C=...
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1answer
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Preference for basic conditions in ester hydrolysis

It has occurred to me that it is very common see the use of basic conditions for ester hydrolysis in various syntheses. One such sequence commonly seen in the case of the malonic ester synthesis is: $...
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2answers
14k views

Does Br2/H2O oxidize all aldehydes?

In many books, it is mentioned that aldehydes are easily oxidized even by mild oxidizing agents. However, I have never seen bromine water explicitly mentioned. But in the carbohydrates chapter, it is ...
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1answer
192 views

Oxalate Anion MO Diagram

I figured I’d study $\ce{C2O4^2-}$ as an organometallic ligand, and found that it is weak field (pi donor). I hence decided to construct a MO diagram. The oxalate anion is of D2h symmetry, so one ...
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0answers
97 views

How can the ketone in a β-ketoester be protected during hydride reduction?

I am supposed to find what X is. I know that $\ce{LiAlH_4}$ will convert all carbonyl groups to alcohols, and the ester group is being reduced. The only way of ending up with a ketone that I can think ...
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1answer
62 views

Reagents in Krapcho's decarboxylation

Krapcho's decarboxylation is a reaction involving esters with a electron-withdrawing group $\beta$ to the carbonyl group and halide ions. It is typically conducted with $\ce {LiCl}$ and $\ce {DMSO}$ ...