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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8
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1answer
332 views

On the mechanism of the nitrogen-removal step of the Wharton olefin synthesis

In today’s reaction seminar, the Wharton transposition made an appearance. In our practice case it started from the epoxide as in scheme 1 below as on Wikipedia; Kürti/Czakó (page 482) begin from the ...
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1answer
889 views

Reaction of hydrazine and hydroxylamines with carboxylic acids

Carboxylic acids and their derivatives on reaction with hydroxylamine $\ce{NH2OH}$ and hydrazine $\ce{N2H4}$ give hydroxamic acids and acid hydrazides, respectively, through acyl nucleophilic ...
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1answer
597 views

How do I arrive at the α-trimethylsilyloxy ketone from an unmodified ketone using TMSCl, triethylamine and mCPBA?

I'm confused about what is going on here. I gather that step 1 is typically supposed to protect an OH group, but there isn't any in the starting material.
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1answer
189 views

Intramolecular lactonisation in an unsaturated carboxylic acid

I am having some trouble figuring out how this reaction proceeds: Attempt 1: The most obvious thing to do is deprotonate the acid group. I tried using the carboxylate group to attack the alkene, ...
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1answer
1k views

Resonance of carbonyl

Carbonyl has two resonance structures, where the $\pi$-bond between C and O breaks and the electrons "move" to the oxygen atom. This gives an empty p-orbital in carbon and a p-orbital in oxygen with ...
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1answer
14k views

Mechanism for decarboxylation

Propose a mechanism for the following transformation. I gather that this mechanism might be similar to decarboxylation of keto acids: However, I am unsure of how to begin.
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1answer
3k views

Why is enol content higher in non-polar solvents?

Apparently, for keto-enol tautomerism, the enol content of a given carbonyl compound increases when in a non-polar solvent. What is the reason for this?
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1answer
251 views

Why don't Gringard Reagents react with carbonyls at the alpha position? [duplicate]

According to many texts, the reason why Gringard reagents cannot be used with alcohols is because the Gringard reagent is a strong base, which would deprotonate the alcohol. ($p\pu{K}_b$ of Gringard $\...
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2answers
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Rearrangements of α-aminoketones in Clemmensen reduction

What is the possible mechanism for this reaction? Activated zinc in presence of concentrated hydrochloric acid is used for Clemmensen reduction, that is conversion of ketone group to methylene group. ...
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1answer
1k views

Sodium metal in acetone

When I place a chunk of 99,99% pure sodium metal in a beaker of (100% chemically pure) acetone, the sodium metal starts reacting and dissolving into the acetone and it forms a yellow/brown liquid. ...
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1answer
476 views

Why carboxylic group gets protonated preferantially on carbonyl oxygen?

When carboxylic group gets protonated, by strong acid, proton binds rather to carbonyl oxygen, then to hydroxyl. Is that really true? Or maybe it's a case of kinetic vs thermodynamic stability?
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1answer
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Byproducts of LiAlH4 reduction of amides

I know that $\ce{LiAlH4}$ is able to reduce amides into amines, e.g. benzamide into benzylamine. However, I am unsure what other by-products are formed as a result. $$\ce{LiAlH4 + C6H5CONH2 -> ...
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Reactions of Grignard Reagents with amides

Can Grignard reagents add to amides? It appears from the synthetic pathway shown below that there has been some form of nucleophilic substitution at the carbonyl group. Source: 49th IChO Preparatory ...
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413 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 ...
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1answer
413 views

Glycoside Formation Reaction

Whenever we add $\ce{H+}$/ Ethanol to glucose in its hemiacetal form, why doesn't pinacone/pinacolone rearrangement take place in place of nucleophillic substitution. The product would lead to ...
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1answer
4k views

Why can't Schiff's reagent distinguish between glucose and fructose?

I have heard that Schiff's base only gives a positive test for aldehydes. Glucose is an aldehyde. However, I was told that glucose doesn't give a positive Schiff's base test. Is this correct? If so, ...
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533 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 ...
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1answer
380 views

Hydrolysis of an ester

An organic compound X of formula $\ce{C5H10O2}$ forms two compounds when boiled in aqueous sodium hydroxide solution. One of these compounds forms a ketone when treated with acidified potassium ...
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0answers
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What is the reason for colour in 2,4-Dinitrophenylhydrazine derivatives?

2,4-Dinitrophenylhydrazine is an important laboratory reagent for the detection of Carbonyl (C=O) group. It reacts with Carbonyl group by the typical Nucleophilic Addition-Elimination reaction and if ...
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79 views

Ease of reduction of carboxylic acid derivatives [duplicate]

Lithium aluminium hydride (LAH) is able to reduce aldehydes, ketones, carboxylic acids and esters. However, sodium borohyride ($\ce{NaBH4}$) is unable to reduce carboxylic acids and esters. Given that ...
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1answer
410 views

Single electron reduction of ketone by Na or Zn

Whenever we add Na or Zn metal to a ketone, why does the electron prefer to attack the carbonyl bond and form a radical, instead of removing the acidic hydrogen and forming an enolate and $\ce{H2}$ ...
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1answer
5k views

Decarboxylation of Salicylic acid

I would like to know how and under what conditions can decarboxylation of salicylic acid (o-hydroxybenzoic acid) occur. I couldn't find any sources for it online. Here are some reasons I think it ...
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1answer
201 views

Ketone/aldehyde synthesis from N-acylazetidines or aziridines

A common principle in organic chemistry is to make sure the product is less reactive than the starting material, to prevent overreaction. So, for example, the treatment of an ester with a Grignard ...
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1answer
648 views

Mechanism of Hofmann Rearrangement Reaction

In the Hofmann Rearrangement Reaction (in basic medium), when $\ce{RNH-}$ ion is produced, why does it not attack $\ce{Br2}$ or take $\ce{H+}$from the amide itself? Also, why does it take $\ce{H+}$ ...
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1answer
93 views

What can be used to thionate a monosubstituted urea?

I'm looking to make a thiourea from a monosubstituted urea. I haven't found any references that use Lawesson's Reagent, which I have been using for the thionation of di and trisubstituted ureas. Is ...
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1answer
147 views

Is there a systematic naming system to name carbonyl derivatives?

I had asked a question earlier about how the “$\ce{-COOCl}$” functional group would be named. I had received a satisfactory answer that helped me completely understand how that compound was named. ...
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2answers
684 views

How would the “-COOCl” functional group be named?

I had this question that has been bouncing around for over 2 years. Basically, I imagined this molecule: This molecule, as far as my former (and current) knowledge of nomenclature goes, couldn't be ...
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2answers
599 views

Rate-determining step of Claisen condensation

If we use a strong base such as LDA or NaH, will the rate-determining step change from enolate ion formation to nucleophillic acyl substitution step?
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1answer
9k views

Mechanism of the reaction of cyclohexanone and nitric acid to form Adipic acid

Can I get some help in figuring out the mechanism for this reaction. Adipic acid is a molecule with two carboxylic groups,but I can't see how that happens. My initial thoughts involved that the ...
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1answer
370 views

Selectivity in acetonide formation from a polyol

In my total synthesis lecture notes the above example is given in which a polyol is reacted under acetonide forming conditions. The notes point out that this product is the only product, no other ...
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1answer
261 views

Why is nitrosobenzene electrophilic on O in organocatalytic oxygenations?

In 2003 Zhong1 and MacMillan2 reported the use of nitrosobenzene, PhNO, in the organocatalytic asymmetric α-oxygenation of carbonyl compounds: which is all nice, except for the slightly ...
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314 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:...
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1answer
219 views

Chelation-controlled aldol: why is the α substituent pseudo-axial?

In this Mukaiyama aldol reaction, taken from a 1999 paper by D.A. Evans,1 when $\ce{TiCl4}$ was used as the Lewis acid catalyst, the aldehyde 4a formed a chelated intermediate whereas 4b did not (due ...
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2answers
347 views

What's the reason for the instability of ethylene dione?

Ethylene dione, with a chemical formula $\ce{C2O2}$ and an IUPAC name of ethene-1,2-dione, is an oxocarbon. The Wikipedia page says: The existence of $\ce{OCCO}$ was first suggested in 1913. ...
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0answers
812 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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2answers
1k views

Nucleophilic acyl substitution: conversion of butanoic acid to butanenitrile [closed]

How can I convert the carboxylic acid functional group into a nitrile?
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1answer
3k views

Reduction of a ketone to an alkane

What is the mechanism for the reduction of ketone to alkanes using $\ce{H2}$, $\ce{Pd/C}$ in ethanol? Searching on Google mostly yields the reduction of ketones to secondary alcohols using LAH.
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1answer
501 views

How to form an acetal from an enol ether?

I am having trouble understanding how the protecting group (ethylene glycol) is applied to the alkene next to the ether of highlighted step above. I thought maybe TsOH protonates the alkene as seen in ...
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1answer
5k views

Why does the Rosenmund reduction stop at the aldehyde stage?

In the Rosenmund reduction, an acyl chloride can be reduced to an aldehyde by hydrogenation over a palladium catalyst poisoned with barium sulfate. Why isn't the aldehyde product further reduced to ...
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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 ...
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1answer
45 views

Does the oxidation for all the aliphatic monoaldehydes to carboxylic acids have the same value of electrode potential?

I have been wondering on this for quite a while. Consider aliphatic monoaldehydes. If I oxidize them, we get corresponding monocarboxylic acids. We can use certain oxidizing agents to perform the ...
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1answer
1k views

In the bicarbonate ion, why can the hydrogen not bond to the carbon?

I've been studying electrophiles and nucleophiles recently, including how the carbonate ion ($\ce{CO3^2-}$) is stabilised through resonance. While drawing the model for bicarbonate, however, I ...
4
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1answer
872 views

Why bond energy of acetone is more though it is more polar than formaldehyde?

I was going through the general properties of carbonyl compounds and then found this (in the pic) data, where it says that dipole moment of acetone (if we assume $\ce{R = -CH3}$) is more than ...
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3answers
5k views

Is there intramolecular hydrogen bonding in salicylaldehyde?

Is there intramolecular hydrogen bonding between the hydroxyl and carbonyl groups? I think personally is that it does but what is concerning me is that I have got no adequate answer or response to my ...
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1answer
10k views

Can hydrogen on platinum reduce carboxylic acids and esters?

Can $\ce{H2/Pt}$ reduce carboxylic acids and esters? I am confused about the reducing nature of hydrogen in presence of platinum. In some books, it reduces carboxylic acid and ester while in others, ...
5
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1answer
106 views

Reduction by hydrosilanes

I was trying to predict the following reaction as part of an organic reaction scheme: I thought that $\ce{Et3SiH}$ would reduce the ester to an aldehyde. But E turned out to be I see that the $\ce{-...
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1answer
653 views

What is the significance of the 2 and 4 positions in 2,4-DNP?

(2,4-Dinitrophenyl)hydrazine, a popular laboratory reagent is used to identify carbonyl compounds by forming 2,4-dinitrophenylhydrazones, which are often red or yellow colored precipitates. Why is ...
0
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1answer
69 views

Will an acyl chloride be attacked by water molecule to form carboxylic acid?

$\ce{H2O}$ molecules can act as a nucleophile. So it should attack the carbonyl carbon. However, I think that that when the $\ce{O-}$ "kicks back" it will once again remove the water molecule keeping ...
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3answers
503 views

Can any other common reagent other than than H3PO4 cause this conversion?

Can any other common reagent other than than $\ce{H3PO4}$ cause this conversion? What about (conc) $\ce{H2SO4}$ or (conc) $\ce{HNO3}$ or (conc) $\ce{HCl}$?
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138 views

In the mechanism of Cannizzaro reaction why does the hydride migrate rather than the benzene ring? [duplicate]

The hydride ion is not very stable. On the contrary a negative charge on a $\ce{sp^2}$ on the benzene ring would be much more stable. So why doesn't the benzene ring migrate instead of the hydride, as ...

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