Chapter 6: 6.5 Ozonolysis

Question 1

List:

Characteristics of Ozonolysis Reactions

(6 points)

Answer 1

1. Occur in multiple steps
2. Proceed via a five-membered ring intermediate
3. Serve to cleave the carbon-carbon double bonds to make new carbon-oxygen double bonds
4. A disubstituted alkene carbon atom will always generate a ketone product
5. A monosubstituted alkene carbon atom will make either an aldehyde or an acid - this depends on the work-up step!
6. A reductant (NaBH4) can also be used in the work-up to make alcohol

Question 2

What are the three different work-ups?

Answer 2

1. Me2S
2. H2O2
3. NaBH4

Question 3

Explain:

Me2S work-up

Answer 3

A mild work-up to give the aldehyde from the monosubstituted carbon atom

Question 4

Explain:

H2O2 work-up

Answer 4

A strong work-up to give the acid from the monosubstituted carbon atom

Question 5

Explain:

NaBH4

Answer 5

A reductive work-up to give the alcohol instead of the carbonyl

Question 6

True or False:

You must know the mechanism of ozonolysis

Answer 6

False, it is a pretty complicated process so you don’t need to know it

Question 7

What can also undergo ozonolysis?

Answer 7

Alkynes

Question 8

What yields from alkynes undergoing ozonolysis?

Answer 8

2 new carboxylic acids (useful functional groups)