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What is Aza enolate?

What is Aza enolate?

An aza-enolate is formed when an imine is treated with LDA, or another strong base to generate a nitrogen equivalent of an enolate. To make an aza-enolate we must use a primary amine to initially generate the imine, which can then undergo deprotonation. An enamine is made from a secondary amine.

What role might an enolate play in a reaction?

The special importance of the reaction is that it forms a new C-C bond. It does this, in basic solution,by using the enolate as a nucleophile which adds to the electrophilic carbonyl carbon. The enol is more so because the -OH substituent donates electrons to the pi bond (see resonance structures for the enol, above).

What stabilizes an enolate?

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.

What does an enolate do?

Enolates are organic anions derived from the deprotonation of carbonyl compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds.

How are enolates alkylated in the alpha position?

Alkylation of Enolates Enolates can be alkylated in the alpha position through an S N 2 reaction with alkyl halides. During this reaction an α hydrogen is replaced with an alkyl group and a new C-C bond is formed. The limitations of S N 2 reactions still apply.

What happens to the diester of diethyl malonate after alkylation?

Step 1) Reacting diethyl malonate with sodium ethoxide (NaOEt) forms a resonance-stabilized enolate. Step 2) The enolate is alkylated via an S N 2 reaction to form an monoalkylmalonic ester. Step 3) After alkylation, the diester undergoes hydrolysis with sodium hydroxide to form a dicarboxylate.

Why does carboxylic acid inhibit the formation of enolates?

In addition, the acidic hydrogen on carboxylic acids inhibits the formation of an enolate, making direct alkylations difficult. Ester, including lactones, and symmetrical ketones readily undergo direct alkylation. However, direct alkylations, like all enolate-based reactions, will form a racemic mixture if the alkylated alpha carbon is chiral.

How does the synthesis of malonic ester take place?

Malonic ester synthesis takes place in four steps: Step 1) Reacting diethyl malonate with sodium ethoxide (NaOEt) forms a resonance-stabilized enolate. Step 2) The enolate is alkylated via an S N 2 reaction to form an monoalkylmalonic ester. Step 3) After alkylation, the diester undergoes hydrolysis with sodium hydroxide to form a dicarboxylate.