Carboxylic Acid & Derivative Reactions Flashcards
What can we use to complete this reaction?
LiAlH4 followed by acid workup
What kind of reactants are necessary for a decarboxylation reaction to occur?
Acidic amino acid, beta-keto acid, dicarboxylic acid
Decarboxylation mechanism:
What product will form when the following carboxylate ion (pyruvate) undergoes a decarboxylation reaction in the presence of HS-CoA?
The decarboxylation of pyruvate produces acetyl-CoA. This reaction is an example of enzyme-catalyzed oxidative decarboxylation.
How do you determine the possible reactants when presented with this anhydride product?
- Since this is an anhydride you should know that to form an anhydride requires either the combination of an acyl chloride and carboxylic acid OR a condensation reaction of two carboxylic acids.
- Look at the molecule and draw two lines on each side of the ester O. Number the carbons.
- One side of the line makes up the acyl chloride and the other side makes up the carboxylic acid or vice versa. Different combinations can be made to achieve the same product.
Which is more likely to react (better electrophile), an anhydride or an amide?
Anhydride because it has a strong EWG (stronger inductive effect) due to the adjacent O, whereas an amide has an adjacent N which has less inductive effect.
EWG make better LGs and cause electrophile to be more reactive.
How does the number of electron-withdrawing groups affect the acidity of a carboxylic acid?
The more electron-withdrawing groups, the stronger the acid. These groups stabilize the conjugate base by delocalizing the electron density of the negative charge.
How is the acidity of a carboxylic acid affected by the electronegativity of its substituents?
More electronegative group near a carboxyl group increases the acidity.
IUPAC suffix for an ester:
-oate
How is an ester named according to IUPAC?
The alkyl group from the —o—- (alcohol) side is named first as a substituent whereas the body chain makes up the =O side
When an alcohol and a carboxylic acid are combined in solution and heated, what reaction is expected to occur? What product(s) will form?
An esterification reaction will occur between the alcohol and carboxylic acid. The expected products include an ester and water.
Acid-Catalyzed epoxide opening mechanism
*Nucleophile attaches to more substituted side
Base-Catalyzed epoxide opening mechanism
*strong base+ strong nucleophile attacks less substituted C in an SN2 manner
*Causes inversion of configuration where the nucleophile attacks
Out of all the carboxylic acid derivatives, which is the most reactive?
Acyl halide, which is the least stable because it has no resonance, Also has induction (which increases reactivity, electrophilicity of the C).
NaBH4 is a reducing agent, what happens if it reacts with a carboxylic acid?
NaBH4 is not strong enough to reduce a COOH, therefore it remains the same.
General mechanism of nucleophilic acyl substitution.