Respuesta :
Leucine and methionine are the amino acids formed using the n-phthalimido malonic ester synthesis.
The steps involved in phthalimido malonic ester synthesis:
Step 1: Deprotonation To Give An Enolate
In the first step, a base (CH3O– in this case) removes the most acidic proton from the ester (on C2 here, with a pKa of about 13) to give an enolate. The resulting enolate can be drawn as one of two resonance forms.
Step 2: SN2 Reaction Of The Enolate Nucleophile With An Alkyl Halide Electrophile.
Enolates are great nucleophiles. In the second step, the enolate acts as a nucleophile in an SN2 reaction to form a new C-C bond.
Step 3: Acidic Ester Hydrolysis
Acid and water are added to perform the aqueous hydrolysis of the ester to a carboxylic acid.
Step 4: Decarboxylation To Give An Enol
When carboxylic acids have a carbonyl group (C=O) two bonds away, they can readily lose carbon dioxide, because the carbonyl can act as an electron “sink” for the pair of electrons coming from the breaking C–C bond, forming an enol. This is called “decarboxylation”. Note how this is also the case for carboxylic acids with a ketone two bonds away, so-called “β-keto acids”.
Step 5: Tautomerization Of The Enol Back To The Carboxylic Acid
The enol that is formed is not a stable species. It can undergo transformation into its constitutional isomer: in this case, a carboxylic acid. These two constitutional isomers are in equilibrium with each other, although the “keto” form (with the carbonyl group) is greatly favoured. This process is called "tautomerism".
To learn more about SN2 mechanism:https://brainly.com/question/7213902
#SPJ4
