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.

133 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
12
votes
1answer
6k 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-...
8
votes
0answers
393 views

Sulfonyl azides: diazo or azide transfer?

Sulfonyl azides, $\ce{RSO2N3}$, are capable of acting as sources of electrophilic azide ("$\ce{N+3}$"), but are also capable of effecting diazo transfer, as shown in the scheme below, taken from ref 1:...
7
votes
0answers
221 views

The Action of Nitrogen Iodide on Methyl Ketones

I recently encountered two old publications on action of nitrogen iodide on various compounds (Ref.1 and Ref.2). Between them, Ref.1 described the idoform formation by methyl ketones upon treatment of ...
7
votes
0answers
235 views

How can I solve this synthesis?

I have this task to do: My solution: Is that possible? Can you please help me with the steps 2 and 3? This is what I did, but my teacher told me I should make the diketone (compound no. 5) from ...
6
votes
0answers
135 views

Comparison of C=O bond strength in metal carbonyls

Find the weakest $\ce{C=O}$ bond among $\ce{[Mn(CO)6]+},$ $\ce{Fe[(CO)5]},$ $\ce{[Cr(CO)6]}$ and $\ce{[V(CO)6]-}.$ I thought the $\ce{C=O}$ bond strength would be lowest in $\ce{[V(CO)6]-}$ since the ...
6
votes
0answers
343 views

pKa of different sites of butanone

From what I can tell, deprotonation of the central hydrogen leads to the more thermodynamically stable product (most substituted double bond. i.e. most stabilization by hyperconjugation). Therefore, ...
5
votes
0answers
227 views

Optical activity of tartaric acid

The meso-form of tartaric acid is optically inactive due to the plane of symmetry. But how are these forms able to show optical activity when the σ-bonds can freely rotate, which can change the ...
5
votes
0answers
137 views

Does periodic acid cleave acetals?

Recently, I started reading about the cleavage reactions done by $\ce{HIO4}$. I came across a statement which read $\ce{HIO4}$ can't cleave acetals but it can cleave hemiacetals. But when I tried to ...
5
votes
0answers
82 views

Can a per-acetylated sugar anomerize?

So I have a question concerning a reaction mechanism for the reaction below. I know for certain that I get the alfa anomer, but I can't explain it. When I draw out the mechanism it doesn't make sense ...
5
votes
0answers
304 views

Reaction of alpha hydroxyketone with KOH

What happens when 2-hydroxycyclohexan-1-one (an alpha hydroxyketone) reacts with aqueous $\ce{KOH}$? I tried something like Favorskii rearrangement, but it's wrong because OH isn't a good enough ...
5
votes
0answers
326 views

Stability of extended enolates

I'd expect an extended enolate to be more stable than a normal enolate, when both can form, but my textbook suggests otherwise. What is the stability of an extended enolate compared with a normal ...
5
votes
0answers
465 views

Why does the keto tautomer of guanine have lower energy?

Looking at the keto and enol forms of guanine, it would seem as if the enol form is more stable, due to the fact that aromaticity is established with the enol form. However, according to a question on ...
5
votes
1answer
3k views

Protonation of Carbonyl oxygen in Fischer Esterification

In the Fischer Esterification, why is it the acid's carbonyl oxygen getting protonated and not the hydroxyl oxygen? This protonation occurs in Step 1 of the mechanism below. I read in some textbooks ...
4
votes
0answers
57 views

2-Iodoxybenzoic acid oxidation reaction

I was thinking about using 2-Iodoxybenzoic acid to selectively oxidize primary alcohols to aldehydes. I've found papers using various solvents like acetone/water mixture1, 2-methyl-2-propanol2, DMSO ...
4
votes
0answers
56 views

Reactivity order of DIBAL-H and diborane with esters and acids

I have been taught in class that DIBAL-H is more reactive towards esters than carboxylic acids while opposite is true for diborane. Also DIBAL-H mentioned is taken under low temperatures (−78 °C). I ...
4
votes
0answers
134 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 ...
4
votes
0answers
81 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 $\alpha$, $\beta$-...
4
votes
0answers
1k views

Effect of H-bonding on o-nitrobenzoic acid

My argument here is regarding the acidity of o-nitrobenzoic acid being greater than p,m-nitrobenzoic acid. In o-nitrobenzoic acid, there is an intramolecular hydrogen bond which makes the bond ...
4
votes
0answers
368 views

Regioselectivity of the Beckmann rearrangement

It seems to be that the Beckmann rearrangement is a nice way to prepare secondary amines. This can be achieved by removal of oxygen via the use of $\ce{HI}$/$\ce{P}$. However, if ketones are used, ...
4
votes
0answers
265 views

Does alcohol hydrogen in the enol tautomer of a β-dicarbonyl have sp² character?

My reasoning for the somewhat implausible "$\mathrm{sp^2}$" character of the hydrogen between these two oxygens on the enol structure of the right comes from recognizing that if it were, then we would ...
4
votes
0answers
286 views

What is the average chain length of a glutaraldehyde crosslink between primary amines?

Imagine I'm performing a primary amine to primary amine (i.e. PA to PA) crosslinking reaction at $37~^{\circ}\mathrm{C}$ in phosphate-buffered saline (pH $\approx 7.4$) with glutaraldehyde drawn from ...
4
votes
1answer
2k views

Why are acid catalysed reactions of carbonyl compounds reversible?

I am currently studying aldehydes and ketones and their reactions. I've noticed that acid catalysed reactions are represented with reversible arrows, while base catalysed reactions are shown with ...
3
votes
0answers
49 views

Does the nucleophilic substitution in an acid chloride always proceed through a tetrahedral intermediate?

I am a beginner in organic chemistry and would like to ask for the mechanism for the nucleophilic substitution of carbonyl groups from acid chloride - especially regarding the tetrahedral intermediate?...
3
votes
0answers
68 views

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 ...
3
votes
0answers
326 views

How does a cyclization occur with a carboxylic acid and (CF3CO)2O?

The product of the reaction below is unsaturated, bicyclic ketone, but I'm confused as to how (CF3CO)2O reacts with it to cause the cyclization. There is no base involved so I don't know how the ...
3
votes
0answers
28 views

Will phosphorous Ylide participate in carbene generation and insertion?

The following question was sent to me . The answer for this question was given to me as option b I attempted it as following , recognizing the first step as a ylide reaction with a carbonyl compound....
3
votes
0answers
183 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 ...
3
votes
0answers
693 views

Why does the proton transfer from the oxygen to the nitrogen atom in imine formation not occur through an intramolecular process?

In my book Organic Chemistry by David Klein, 2nd edition, the book shows that the oxygen atom first takes a proton from an acid, then, the conjugate base of the acid takes a proton from the nitrogen ...
3
votes
0answers
2k views

Which enolate of butanone is more stable?

Consider butanone (A) and its two possible enolates B & C. Which of the two enolates will be more stable? B because of the more stable primary carbanion, or C because of more stable enolate (...
3
votes
0answers
2k views

Enol content of acetylacetone and ethyl acetoacetate

Why is the enol content of acetylacetone higher than that of acetoacetic ester? Hydrogen bonding stabilisation is present in enol form of both of them. I cannot figure out which factor makes one ...
3
votes
0answers
101 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 ...
3
votes
0answers
1k views

Why do electronegative heteroatoms increase C=O stretching frequency (bond strength)

Why does a more electronegative heteroatom (i.e. $\ce{Cl}$ or $\ce{O}$) increase the stretching frequency of a carbonyl? I'd suspect it's that they donate their lone pairs and we end up with a ...
3
votes
1answer
172 views

Do all α-hydroxy ketones give Tollens’ test?

It is well known that terminal α-hydroxy ketones give Tollens’ test, via tautomerisation. Also, α-hydroxy ketones flanked by aromatic groups give Tollens’ test, such as benzoin. But do all α-hydroxy ...
3
votes
2answers
78 views

How can you qualitatively tell when the hydrolysis of aspirin is over?

I'm doing an experiment on the effect of temperature on the time taken to produce acetic acid and salicylic acid. Are there any qualitative observations I can make about when the reaction has finished?...
3
votes
1answer
983 views

Mechanism for conversion of imide to ester with NaH

What is the mechanism of this reaction? My proposed mechanism is shown below, would it work?
2
votes
0answers
46 views

When do the Wolff-Kishner Reduction and Clemmensen Reduction not take place for carbonyl compounds?

I came across some examples of organic compounds with acidic groups that didn't undergo the Clemmensen reduction. So, I was wondering which types of compounds the two reagents cannot reduce. Also, why?...
2
votes
0answers
46 views

Why aren't both alpha-carbons halogenated when acetone reacts with chlorine under UV?

My book shows the following reaction: Why is only one alpha carbon halogenated? I googled, but couldn’t find anything on it.
2
votes
0answers
64 views

Does KCN prefer SN2 or nucleophilic addition?

If we have a 1° halide that also contains a carbonyl group (like 5‐chloropentan‐2‐one), and we add 1 mole of KCN in DMSO to it, what will happen? Will the SN2 product by substitution of chlorine or ...
2
votes
0answers
37 views

Number of π electrons in all trans-2,4,6-octatrienoic acid

Sketch the Lewis structure of all trans-2,4,6-octatrienoic acid. (a) Consider the delocalized π electrons. Employ the particle-in-a-box model. Drawing on your knowledge about the occupation of ...
2
votes
0answers
22 views

Which one out of a keto group or a hydroxyl group would get protonated first if both are present in a compound (attachment)

In the solution provided by my teacher he protonated the ketone, moved the +ve above by resonance did methyl shift and then did dehydration to form a benzene type system. Is this only because for this ...
2
votes
0answers
83 views

Does 2‐indanone form a stable hydrate?

Following up the question Formation of a stable hydrate. I understand that for cyclopropanone the change in hybridization is the reason for stabilization of hydrate since it relieves the angle strain. ...
2
votes
0answers
53 views

Comparing melting points of substituted benzaldehydes

The correct decreasing order of melting point for the given organic compounds is: 3 has maximum melting point because of intermolecular hydrogen bonding. I am unable to predict rest of the order ...
2
votes
0answers
127 views

Product of the reaction of ethyl acetoacetate with alkaline benzoyl chloride followed by addition of ammonium chloride

What does this β-keto ester give when reacted with $\ce{PhCOCl/NaOH}$ followed by $\ce{NH4Cl(aq)}?$ According to me, the $\ce{PhCOCl}$ should react with $\ce{NaOH}$ forming benzoic acid which should ...
2
votes
0answers
124 views

Why aren't nitriles very good electrophiles?

I was wondering why nitriles do not react as electrophiles like carbonyl unless they have to, given that the C-N triple bond is still pretty polarized. The LUMO will be higher in energy than a ...
2
votes
0answers
81 views

What is the product of following iodoform reaction?

Question Attempt I think the product A would be as I have attempted below, but I am getting the answer as A but book says D. Where am I wrong? Please help.
2
votes
0answers
73 views

Bond strength of carbon compounds

I read online that C=O is more stronger than C=N and the reason behind this was, 'Since bond between C and O is more polar hence it will have a slightly higher ionic nature than C and N. As we know ...
2
votes
0answers
51 views

Steric inhibition of resonance in substituted benzoic acid

Why does attaching an $\ce{-NO2}$ group at the ortho position of benzoic acid cause $\ce{-COOH}$ to become perpendicular to the plane of the benzene ring? Why doesn't the nitro group get pushed out ...
2
votes
0answers
227 views

Reaction of diamines with carboxylic acids to form imidazole

I've recently came across this reaction and my guess is that firstly an amide forms that later reacts with the second amine group. Is this a general reaction? Does it matter if the compounds used are ...
2
votes
0answers
149 views

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 ...
2
votes
0answers
215 views

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, ...