First, aldehydes are more reactive acceptor electrophiles than ketones, and formaldehyde is more reactive than other aldehydes. … the condensation of ketones with aryl aldehydes to form α,β-unsaturated derivatives is called the Claisen-Schmidt reaction.

Do ketones undergo aldol condensation?

Aldehydes or ketones with alpha hydrogen respond With any strong base such as NaOH, KOH and Ba(OH)2 and produces aldol as product. This reaction doubles the number of carbon atoms of the original aldehyde or ketone. To dehydrate the aldol compound, it can be heated alone or with I2.

Can ketones do an aldol reaction?

« Aldol » is an abbreviation for aldehyde and alcohol. When an aldehyde or ketone enolate reacts with the carbonyl group of another molecule at the α-carbon under basic or acidic conditions To obtain β-hydroxyaldehydes or ketones, this reaction is called an aldol reaction.

What types of aldehydes and ketones undergo aldol condensation?

all Aldehydes with alpha-hydrogen Aldol condensation is carried out.

Which does not undergo aldol condensation?

Carbonyl compounds must contain alpha-hydrogen atoms for aldol condensation. Therefore, propionaldehyde and acetaldehyde are aldehydes that can undergo aldol condensation. …so aldehydes that do not undergo aldol condensation are Trichloroacetaldehyde, benzaldehyde and formaldehyde.

Aldol condensation and unsaturated ketones

26 related questions found

2 Does phenylacetaldehyde undergo aldol condensation?

(1) Propionaldehyde. (2) Trichloroacetaldehyde. (3) 2-Phenylacetaldehyde.

Can benzaldehyde undergo aldol condensation?

Benzaldehyde does not undergo aldol condensation.

Which types of aldehydes undergo aldol condensation?

Aldol condensation occurs in an aldehyde with an α-hydrogen with a dilute base, giving β-Hydroxyaldehydes are called aldols. This reaction is often called an aldol condensation.

What is an example of an aldol condensation?

Aldol condensation is a condensation reaction in organic chemistry in which an enol or enol ion reacts with a carbonyl compound to form β-hydroxyaldehyde or β-hydroxyketone, and then dehydrated to obtain the conjugated enone.

What does NaOH do to ketones?

Adding a base (such as NaOH) to an aldehyde or ketone will produces a little enolate, which can react with another carbonyl molecule. This reaction is called aldol condensation. This product contains a hydroxyl (-OH) group at the β position of the carbonyl group, hence the name β-hydroxycarbonyl.

Why is aldol condensation reversible?

The dehydration step of the aldol condensation is also Reversible in the presence of acid and base catalysts. Therefore, many α, β-unsaturated carbonyl compounds split into smaller aldehydes or ketones when heated with aqueous solutions of strong acids or bases, a process called retroaldol reaction.

What is the difference between aldol reaction and aldol condensation?

The name aldol is also commonly used, especially in biochemistry, to refer only to the first (addition) stage of the process – the aldol reaction itself – which is catalyzed by an aldolase enzyme. However, The aldol reaction is not a formal condensation reaction because it does not involve the loss of small molecules.

How to improve the yield of aldol condensation?

Can improve the yield of aldol reaction and condensation products By removing water or carbonyl products from the reaction mixture So, remove it from the balance. Aldol reactions are more efficient with aldehydes than with ketones.

How does heat affect ketones?

Aromatic aldehydes form condensation products when heated Cyanide ions are dissolved in an aqueous alcohol solution. This condensation leads to the formation of alpha hydroxy ketones.

Why doesn’t Clayson condensation use NaOH?

Do not use NaOH – the most commonly used bases are NaOR, NaH, NaNH2 and LDA. Insufficient base to deprotonate esters It’s not really acidic. Furthermore, the use of NaOH would lead to a competing reaction for ester hydrolysis. Useful only if five- or six-membered rings can be formed.

Which will produce an aldol condensation?

(Four) Acetaldehyde. Hint: Aldehydes with α-hydrogen undergo self-condensation with dilute or mild bases when heated to form β-hydroxy aldehydes, called aldols (aldehydes + alcohols). This reaction is called aldol condensation. A typical example is the reaction of acetaldehyde with a base under mild conditions.

How do you stop aldol condensation?

Therefore, chemists use a number of methods to prevent this from happening when conducting cross-aldol reactions.

1. Use a more reactive electrophile and a non-enolizable partner.
2. Quantitative preparation of enolate ions.
3. Silyl enol ethers are formed.

Which can show aldol condensation?

All carbonyl compounds containing α-H or α-D Aldol condensation is carried out.

Why catalyze aldol condensation bases?

Enolated aldehydes and enolated ketones, in Presence of acid or base catalysts in aqueous media at high temperature, the reaction is carried out to obtain α, β-unsaturated aldehydes or α, β-unsaturated ketones as products, respectively. This reaction is called aldol condensation.

Does aldol condensation require heating?

Essentially, the difference is Aldol condensation requires heat, because it just helps to eliminate water. Without the heat, you’ll mostly get add-ons.

Why is NaOH used in aldol condensation?

sodium hydroxide Self-condensation occurs because its compounds contain alpha-hydrogen atoms β-Hydroxyaldehyde (an aldol) is 3-hydroxybutyraldehyde. This compound, upon further heating, will eliminate water molecules forming the aldol condensation product, crotonaldehyde or But-2-en-al.

Does cyclohexanone undergo aldol condensation?

When cyclohexanone undergoes aldol condensation in the presence of a base, it will produce A beta-hydroxy ketone. … -Alcoholates deprotonate water molecules, produce hydroxides, and form aldols.

Does C6H5CHO undergo aldol condensation?

Aldol condensation involves the addition of the aldehyde (or ketone) group of one molecule of a carbonyl compound (aldehyde or ketone) to the alpha-hydrogen atom of another molecule. Acetaldehyde Has an α-hydrogen atom and undergoes aldol condensation. Benzaldehyde without alpha-hydrogen atoms does not.

Can trimethylacetaldehyde undergo aldol condensation?

The chemical formula of acetaldehyde is, which contains a -hydrogen atom, but in trimethylacetaldehyde, there is no -hydrogen atom, so, no aldol condensation reaction.