Carboxylic acid reactions

Question 1

How can carboxylic acids be synthesized?

What are the starting materials and reagents?

Answer 1

Oxidation of primary alcohol and aldehyde, or oxidative cleavage of an alkene.
Primary alcohol + strong oxidant like hot KMnO4
Aldehyde + mild oxidant like cold KMnO4
Oxidative cleavage uses O3 and H2O2

Question 2

What is the mechanism for nucleophilic acyl substitution?

Answer 2

Nucleophile (electronegative) attacks the carbonyl carbon and the electrons from the carbonyl double bond move to oxygen. The lone pair then reforms the double bond as OH is protonated and leaves as water.

Question 3

What is the product of an amine acting as the nucleophile in nucleophilic acyl substitution?
How are they named?

Answer 3

Amides - lone pair on N attacks carbonyl carbon.

Naming - replace ‘oic acid’ with -amide, and anything the comes after the nitrogen gets an N prefix.

Question 4

How are esters synthesized?

Naming?

Answer 4

NAS with alcohol as the nucleophile. These are acid-catalyzed, and the carbonyl oxygen is protonated before the oxygen of the alcohol attacks.
The parent carboxylic acid forms the main name, with -ate at the end, and the alcohol-derived substituent is a prefix.

Question 5

How are anhydrides synthesized?

naming?

Answer 5

NAS - nucleophile is another carboxylic acid.

Replace -acid with -anhydride.

Question 6

What is the mechanism for reduction of carboxylic acids, and what are the possible products when using a strong reducer like LiAlH4?

Answer 6

NAS, but continues to attack what was the carbonyl carbon.

carboxylic acid -> aldehyde -> primary alcohol + H2O

Question 7

What is decarboxylation?

Answer 7

An oxidation reaction in which an a,b-ketoacid is oxidized into gaseous CO2 and an enol (which undergoes keto-enol tautomerization). Acid-catalyzed.