How do you know which enolate is more stable?

Of the two resonance structures of the enolate ion the one which places the negative charge on the oxygen is the most stable. This is because the negative change will be better stabilized by the greater electronegativity of the oxygen.

Which base will make 100\% enolate from a general ketone?

LDA
LDA is very good for making enolates of esters, aldehydes and ketones since it can give essentially 100\% (quantitative conversion) to the enolate.

Can an aldehyde become an enolate?

It is there because only the alpha hydrogen can be removed to form the enolate, leaving any other more remote carbons of the aldehyde as a branch.

Can a ketone form an enolate?

In aqueous solution, an aldehyde or ketone which has an alpha type hydrogen can lose it to water, giving hydronium ion and the conjugate base of the carbonyl compound, which is called an enolate.

Which of the following ketone gives more stable in all during Tautomerism?

Answer: C has the most stable enol tautomer.

How enolates are formed?

Enolates, formed by the abstraction of the α hydrogen atom by a strong base, are nucleophiles. Lithium diisopropylamide (LDA) or sodium hydride are required as bases. The site of proton abstraction is related to the acidity of the two possible α hydrogen atoms, which is in the order primary > secondary > tertiary.

What does LDA and THF do?

Ether solvents like tetrahydrofuran (THF) are commonly used for enolate anion formation. With the exception of sodium hydride and sodium amide, most of these bases are soluble in THF. Because of its solubility in THF, LDA is a widely used base for enolate anion formation.

How Enolates are formed?

What do u mean by enolization of ketones?

Enolization or a keto-enol tautomerism is a process of converting a ketone or an aldehyde to a corresponding enol (in acidic conditions) or an enolate (in basic conditions). When we refer to the enolization, we specifically refer to the process that takes you from a ketone or an aldehyde to an enol or an enolate.

How does alkylation of simple enolates form?

Alkylation of Enolates Enolates can be alkylated in the alpha position through an SN2 reaction with alkyl halides. During this reaction an α-hydrogen is replaced with an alkyl group and a new C-C bond is formed.

Why keto form is more stable than?

In general , keto form is more stable than enol form due to greater bond energy of c=o. than c=c . But, in some cases enol form is more stable than keto . For example, if bulky phenyl groups are present at sp3 alpha carbon then enol is more stable than keto form due greater bond angle.

How do enolate ions react with aldehydes and ketones?

Enolate ions can also react with aldehydes and ketones by nucleophilic addition. The enolate ion acts as the nucleophile while the aldehyde or ketone acts as an electrophile.

What is the mechanism of action of enolate on acetaldehyde?

Since acetaldehyde is susceptible to nucleophilic attack, the next stage in the mechanism is the nucleo-philic attack of the enolate ion on acetaldehyde (Fig. 12). The enolate ion has two nucleophilic centers – the carbon and the oxygen – but the preferred reaction is at the carbon atom.

Why is there more enol than enolate in hydroxide anion?

But in the presence of hydroxide anion, there is more enolate than enol, because the equilibrium constant for conversion of an carbonyl compound to its corresponding enolate (10-3) is larger than the K for enolization (10-5). We have seen that the enol can be generated by acid or base-catalyzed mechanisms.

Is enolate ion a nucleophile or electrophile?

The enolate ion acts as the nucleophile while the aldehyde or ketone acts as an electrophile. Since the enolate ion is formed from a carbonyl compound itself, and can then react with a carbonyl compound, it is possible for an aldehyde or ketone to react with itself.