Esters + Ethers + Epoixides

Question 1

Ethers are often used as solvents even though they are relatively reactive. [true or false]

Answer 1

False. Ethers are unreactive.

Question 2

How could you prepare an ether?

Answer 2

Convert alcohol to ether. “condensation”. requires acid catalyst. works best with primary alcohols.

Question 3

Describe Acid-Catalyzed Cleavage.

Answer 3

An Ether using HBr and heat, produces an alkyl halide. Recall : Alcohol + HX -> alkyl halide + water. Also works with cyclic ethers and HI

Question 4

Name 2 ways to prepare an Epoxide.

Answer 4

1. Alkene with peroxy acid.

2. Alkene to vicinal halohydrin, followed by base treatment.

Question 5

Describe Baeyer-Villager Oxidation.

Answer 5

converts ketone to ester using proxy acid oxidation. The oxygen will insert near the larger substituent on ketone. Retention of Configuration after inserting O.

Question 6

Name 2-4 reactions that yield an Ester.

Answer 6

1. Acyl Chlordie with Alcohol
2. Baeyer-Villager Oxidation
3. Carboxylic Acid Anhydrides with Alcohol
4. Fischer Esterification

Question 7

Name 2 ways of Epoxidation.

Answer 7

1. Vicinal Halohydrins w/ Base and water (2 steps)

2. Alkene with peroxy acid (concerted)

Question 8

In Epoxide Ring Opening, explain the difference in Regioselectivity.

Answer 8

Anion Nucleophiles (good Nu, SN2) will attack less crowded carbon. Poor Nucleophiles (carbocation character) attack more substituted carbon.

Question 9

What is Ester Hydrolysis with an Acid ?

Answer 9

Reverse of Fischer Esterification. Ester to Carboxylic Acid. Reagents : water, acid, heat.

Question 10

What is Ester Hydrolysis with a Base ?

Answer 10

Called Saponification. Ester to Carboxylic acid. Irreversible Reaction. first, Nu addition of OH- to C=O. then, tetrahedral intermediate. last, hydroxide induced dissociation of intermediate. Follow with acidic work up to form carboxylic acid. Reagents : water, base, heat