Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
Drawing Instructions: Draw structures corresponding to each of the given names.
1. Draw: 2,2,2-trichloroethanal (chloral)
ANSWER:
POINTS: 1
2. Draw: benzophenone
ANSWER:
POINTS: 1
3. Draw: trans-3-isopropylcyclohexanecarbaldehyde
ANSWER:
POINTS: 1
4. Draw: 5,5-dimethyl-1,3-cyclohexanedione (dimedone)
ANSWER:
POINTS: 1
5. Draw: 2-cyclohexenone
ANSWER:
POINTS: 1
IUPAC Naming Instructions: Provide proper IUPAC names.
7. Name:
ANSWER:
POINTS: 1
8. Name:
ANSWER:
POINTS: 1
Cengage Learning Testing, Powered by Cognero
Page 1
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
9. Name:
ANSWER:
POINTS: 1
10. Name:
ANSWER:
POINTS: 1
11. Name:
ANSWER:
POINTS: 1
Exhibit 19-1
Consider the reaction below to answer the following question(s):
12. Refer to Exhibit 19-1. Write the complete stepwise mechanism for the reaction shown above. Show all intermediate
structures and all electron flow with arrows.
ANSWER:
POINTS: 1
13. Refer to Exhibit 19-1. The substance formed on addition of water to an aldehyde or ketone is called a hydrate or a/an:
a. vicinal diol
b. geminal diol
c. acetal
d. ketal
ANSWER:
POINTS: 1
14. Refer to Exhibit 19-1. The exact position of the equilibrium between ketones/aldehydes and their hydrates depends on
the structure of the carbonyl compound. Although the equilibrium favors the carbonyl compound in most cases,
Cengage Learning Testing, Powered by Cognero
Page 2
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
cyclopropanone forms a stable hydrate. Explain this phenomenon based on the structures of cyclopropanone and its
hydrate.
ANSWER:
POINTS: 1
15. Refer to Exhibit 19-1. Many nucleophilic addition reactions of aldehydes and ketones are catalyzed by acid or base.
Bases catalyze hydration by:
a. making the carbonyl group more electrophilic
b. shifting the equilibrium of the reaction
c. making the carbonyl group less electrophilic
d. converting the water to hydroxide ion, a much better nucleophile
ANSWER:
POINTS: 1
Exhibit 19-2
Consider the data below to answer the following question(s).
Cyanohydrins are important intermediates in the synthesis of α-hydroxycarboxylic acids from ketones and aldehydes. The
nitrile functional group can be hydrolyzed by aqueous acid to yield a carboxylic acid. Nitriles can also be hydrolyzed to
carboxylic acids using aqueous base. Unfortunately, when a cyanohydrin is treated with aqueous base the original
carbonyl compound is isolated.
18. Refer to Exhibit 19-2. The reaction of an aldehyde with hydrogen cyanide is an example of _____ reaction.
a. a nucleophilic substitution
b. an electrophilic addition
c. an electrophilic substitution
d. a nucleophilic addition
ANSWER:
POINTS: 1
19. Refer to Exhibit 19-2. Identify the electrophile in the reaction of benzaldehyde with hydrogen cyanide.
ANSWER: The benzaldehyde is the electrophile in this reaction.
Cengage Learning Testing, Powered by Cognero
Page 3
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
POINTS: 1
20. Refer to Exhibit 19-2. The reaction of benzaldehyde with hydrogen cyanide is catalyzed by the addition of a small
amount of KCN. Write the complete reaction mechanism for the KCN-catalyzed reaction. Show all electron flow with
arrows and show all intermediate structures.
ANSWER:
POINTS: 1
21. Refer to Exhibit 19-2. Formulate a reasonable mechanism for the reaction of the cyanohydrin of benzaldeyhe, shown
above, with aqueous NaOH. Show all intermediate structures and all electron flow with arrows.
ANSWER:
POINTS: 1
22. In the Wittig reaction, a phosphorus ylide adds to a ketone or aldehyde to yield an alkene. Write the complete stepwise
mechanism for the Wittig reaction shown below. Show all intermediate structures and all electron flow with arrows.
Exhibit 19-3
Consider the reaction below to answer the following question(s).
23. Refer to Exhibit 19-3. The nucleophile in this reaction is:
ANSWER:
POINTS: 1
24. Refer to Exhibit 19-3. The catalyst in this reaction is:
Cengage Learning Testing, Powered by Cognero
Page 4
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
ANSWER:
POINTS: 1
25. Refer to Exhibit 19-3. The product of this reaction is called:
a. an ylide
b. an acetal
c. a gem diol
d. a hydrate
ANSWER:
POINTS: 1
26. Refer to Exhibit 19-3. Write the complete stepwise mechanism for this reaction. Show all electron flow with arrows
and show all intermediate structures.
ANSWER:
POINTS: 1
Exhibit 19-4
α,β-Unsaturated aldehydes and ketones can undergo reaction with nucleophiles at the β carbon, as shown below.
27. Refer to Exhibit 19-4. Draw a resonance form for the unsaturated carbonyl that accounts for this reactivity.
ANSWER:
POINTS: 1
Cengage Learning Testing, Powered by Cognero
Page 5
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
28. Refer to Exhibit 19-4. This reaction is called _____ reaction.
a. a 1,2-conjugate addition.
b. an electrophilic addition.
c. a direct addition
d. a 1,2-addition.
ANSWER:
POINTS: 1
Exhibit 19-5
Give the major organic product(s) for each of the following reactions or sequences of reactions. Show all relevant
stereochemistry.
29.
ANSWER:
POINTS:
30.
ANSWER:
POINTS:
31.
ANSWER:
POINTS: 1
32.
ANSWER:
POINTS: 1
Cengage Learning Testing, Powered by Cognero
Page 6
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
33.
ANSWER:
POINTS: 1
34.
ANSWER:
POINTS: 1
35.
ANSWER:
POINTS: 1
36.
ANSWER:
POINTS: 1
37.
ANSWER:
POINTS: 1
38.
ANSWER:
POINTS: 1
39.
Cengage Learning Testing, Powered by Cognero
Page 7
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
ANSWER:
POINTS: 1
40.
ANSWER:
POINTS: 1
41.
ANSWER:
POINTS: 1
Exhibit 19-6
Choose the BEST reagent for carrying out each of the following conversions.
42.
a.
b.
c.
LiAlH4, THF
NaBH4, ethanol
1. DIBAH, toluene
2. H3O+
d. All of the above work well
ANSWER:
POINTS: 1
43.
a. LiAlH4, ether
b. NaBH4, ethanol
c. CrO3, pyridine
d. H2/Pd
ANSWER:
POINTS: 1
Cengage Learning Testing, Powered by Cognero
Page 8
Chapter 19 - Aldehydes and Ketones: Nucleophilic Addition Reactions
44.
a.
1.
2.
1.
2.
PhMgBr, ether
H3O+
b.
PhCH2MgBr, ether
H3O +
c. (C6H5)3P=CHC6H5, THF
d. Li(C6H5)2Cu, ether
ANSWER:
POINTS: 1
45.
a.
1.
2.
1.
2.
PhMgBr, ether
H3O+
b.
PhCH2MgBr, ether
H3O+
c. (C6H5)3P=CHC6H5, THF
d. Li(C6H5)2Cu, ether
ANSWER:
POINTS: 1
46.
a. NaBH4, ethanol
b. CH2PPh3
c. NaOH, H2O
d. All of the above
ANSWER:
POINTS: 1
Cengage Learning Testing, Powered by Cognero
Page 9