Exam2 carbonyl chapter 24 PDF

Preview

Summary

Chapter 24: Carbonyl Condensation Reactions What is the general name for the reaction product formed in an aldol addition reaction? A) -hydroxy carbonyl compound. C) -hydroxy carbonyl compound. B) -hydroxy carbonyl compound. D) ,-hydroxy carbonyl compound. In the correct order, what are the thr...

Description

Chapter 24: Carbonyl Condensation Reactions 1. What is the general name for the reaction product formed in an aldol addition reaction? A) -hydroxy carbonyl compound. C) -hydroxy carbonyl compound. .

D) ,-hydroxy carbonyl compound.

2. In the correct order, what are the three steps in the mechanism of an Aldol reaction? A) Protonation, enolate formation, nucleophilic addition. B)

Enolate formation, protonation, nucleophilic addition.

D) Nucleophilic addition, enolate formation, protonation. 3. Which of the following statements about Aldol reactions with either aldehydes or ketones is true?

B)

Equilibrium favors the starting materials with aldehydes; equilibrium favors the products with ketones. C) Equilibrium favors the products with both aldehydes and ketones. D) Equilibrium favors the starting materials with both aldehydes and ketones.

4. What reaction type is an Aldol reaction? A) nucleophilic substitution B)

electrophilic substitution

Page 1

C)

electrophilic addition

Chapter 24: Carbonyl Condensation Reactions

5. What is the Aldol addition product formed from reaction of the following compound with itself?

A) I

C) III

D) IV

6. What is the Aldol addition product formed from the reaction of (CH3)2CHCH 2CHO with itself?

A) I

B) II

C) III

7. What is the Aldol addition product formed from the reaction of acetone, (CH 3)2CO, with itself?

B) II

C) III

D) IV

8. Which of the following carbonyl compounds will undergo Aldol addition reactions when treated with aqueous sodium hydroxide?

A) I

B) II

D) None of the choices

Page 2

Chapter 24: Carbonyl Condensation Reactions

9. Which of the following carbonyl compounds do not undergo Aldol addition reactions when treated with aqueous sodium hydroxide?

B) II

C) III

D) IV

10. Why is the Aldol reaction often called an Aldol condensation? A) The initially formed -hydroxy carbonyl compound loses a hydroxyl group. B)

The initially formed -hydroxy carbonyl compound loses an oxygen atom.

C)

The initially formed -hydroxy carbonyl compound loses a hydrogen atom.

11. What is the general name for the class of products formed in an Aldol condensation reaction? A) ,-unsaturated carbonyl compound C) ,-unsaturated carbonyl compound D) -hydroxy carbonyl compound 12. Which is the unsaturated carbonyl compound is formed by the dehydration of the following -hydroxy carbonyl compound?

A) I

C) I and II

D) None of the choices

Page 3

Chapter 24: Carbonyl Condensation Reactions

13. Which is the unsaturated carbonyl compound formed in the dehydration of the following -hydroxy carbonyl compound?

B) II

C) I and II

D) None of the choices

14. What aldehyde or ketone is needed to prepare the following compound by an Aldol reaction?

A) I

B) II

C) III

15. What is the name given to an Aldol reaction between two different carbonyl compounds? A) multiple Aldol reaction C) differential Aldol reaction D) versatile Aldol reaction 16. When is a crossed Aldol reaction said to be synthetically useful? A) When both carbonyl compounds have  hydrogens. B)

When both carbonyl compounds have no  hydrogens.

D) When one carbonyl compound has no  hydrogens.

Page 4

Chapter 24: Carbonyl Condensation Reactions

17. In what situation can the yield of a single crossed Aldol product be increased?

B)

The electrophilic carbonyl carbon component is relatively hindered and is used in limited amount. C) The nucleophilic carbonyl component is relatively unhindered and is used in excess. D) The nucleophilic carbonyl component is relatively hindered and is used in limited amount. 18. What is the cyclic product formed in the intramolecular Aldol condensation when the following compound is treated with aqueous NaOH?

A) I

B) II

D) IV

19. What cyclic product is formed in the intramolecular Aldol condensation when the following compound is treated with aqueous NaOH?

B) II

C) III

D) IV

20. What is the general name for the reaction product formed in a Claisen reaction? A) -hydroxy ester C) -keto ester D) -hydroxy ester 21. What reaction type is a Claisen reaction? A) Electrophilic addition B)

Electrophilic substitution

Page 5

C)

Nucleophilic addition

Chapter 24: Carbonyl Condensation Reactions

22. What type of esters can undergo Claisen reactions? A) All esters can undergo Claisen reactions. B)

Only esters with two hydrogen atoms on the  carbon can undergo Claisen reactions. C) Only esters with three hydrogen atoms on the  carbon can undergo Claisen reactions.

23. What is the product of the following Claisen reaction?

A) I

B) II

D) IV

24. What is the product of the following Claisen reaction?

A) I

C) III

D) IV

Page 6

Chapter 24: Carbonyl Condensation Reactions

25. What is the name given to the Claisen reaction between two different esters? A) multiple Claisen reaction B)

differential Claisen reaction

D) versatile Claisen reaction

26. When is a crossed Claisen reaction between two different esters synthetically useful? B)

When both esters have  hydrogen atoms.

C)

When only one of the esters has  hydrogen atoms.

D) When both esters lack  hydrogen atoms. 27. What is the general name of the product of a crossed Claisen reaction between a ketone and an ester? A) -keto ester C) -dicarbonyl compound B)

,-dicarbonyl compound

28. In the correct order, what are the three general steps in the mechanism of a Claisen reaction? A) Enolate formation, elimination, nucleophilic addition.

C)

Elimination, enolate formation, nucleophilic addition.

D) Nucleophilic addition, enolate formation, elimination. 29. What is an intramolecular Claisen reaction called? A) Michael reaction C) Hoffman reaction B)

Robinson reaction

30. In a Michael reaction, what is the name given to the ,-unsaturated carbonyl component? A) Michael donor C) Michael nucleophile B)

Michael enolate

31. In a Michael reaction, where does the nucleophile attack the ,-unsaturated carbonyl component? A) -Carbon C) Carbonyl carbon

Page 7

Chapter 24: Carbonyl Condensation Reactions

D) Carbonyl carbon and -carbon 32. Which of the following compounds cannot serve as a Michael acceptor?

A) I

B) II

C) III

D) IV

33. What are the two starting materials for a Robinson annulation? A) an ,-unsaturated carbonyl compound and an enolate

C)

a 1,5-dicarbonyl compound and an enolate

D) a 1,3-dicarbonyl compound and an enolate 34. What are the names for the two parts of the mechanism in a Robinson annulation? B)

Michael addition and intramolecular aldol reaction

C)

Claisen reaction and intramolecular aldol reaction

D) Aldol reaction and intramolecular Claisen reaction 35. Which of the following compounds can undergo an Aldol with itself?

A) I

B) II

D) Both I and II

Page 8

Chapter 24: Carbonyl Condensation Reactions

36. What is the product of the self-condensation of ethanal (acetaldehyde), shown below?

A) I

C) III

D) IV

37. The following reaction is an example of what type of reaction?

A) Claisen condensation B)

C)

Robinson annulation

mixed Aldol reaction

38. The following reaction is an example of what type of reaction?

C) B)

Aldol self-condensation

Dieckmann condensation

D) Robinson annulation

39. The -hydroxy carbonyl product of an Aldol reaction is oftentimes not the final isolated product, what is the explanation for this result? A) It undergoes elimination, since water is a good leaving group. B)

The hydroxy group is oxidized to a carbonyl.

C)

The hydroxy group reacts with the carbonyl to form a ketal. .

Page 9

Chapter 24: Carbonyl Condensation Reactions

40. Under basic conditions, the Aldol reaction is reversible, but dehydration is not. What is the reason for this difference in reactivity?

B)

The initial Aldol product is an alkoxide, so the reaction is energetically downhill going toward the product. C) The initial Aldol product is an alkoxide, so the reaction is energetically downhill going toward the starting materials. D) Water is a stable molecule. 41. Would this crossed Aldol reaction work well? Why or why not?

B)

Yes, the aldehyde is significantly more acidic, so this enolate can be formed selectively. C) No, the aldehyde is significantly more acidic, so this enolate cannot be formed selectively. D) No, the diketone is significantly more acidic, so this enolate cannot be formed selectively. 42. Of the carbonyl compounds; (1) benzaldehyde, (2) acetophenone and (3) dicyclohexyl ketone, which compound has no -hydrogens? B)

acetophenone

C)

acetone

D) All of these compounds contain -hydrogens 43. Complete this statement: A major difference between the Aldol condensation and the Claisen condensation reactions is that A) the Aldol reaction involves substitution while the Claisen reaction involves addition. B) the Aldol reaction is acid catalyzed while the Claisen reaction is base-catalyzed.

D) the Aldol reaction is base catalyzed while the Claisen reaction is acid-catalyzed.

Page 10

Chapter 24: Carbonyl Condensation Reactions

44. If a Claisen condensation reaction is run using methyl propanoate as the reactant, NaOCH3 is the ideal base. Why is it important to use NaOCH3 and not NaOCH2CH3? A) NaOCH3 is a stronger base than NaOCH2CH3, and this reaction requires a stronger base. B) NaOCH3 is a weaker base than NaOCH2CH3, and this reaction requires a weaker base.

D) NaOCH3 is more soluble than NaOCH2CH3 in organic solvents, and this reaction requires a full equivalent of base to proceed. A full equivalent of NaOCH2CH3 would not dissolve, so the reaction would not proceed. 45. There are several variations of the Aldol reaction. Which of the following types of reactants leads to only one possible product with the Aldol condensation reaction? A) Two different aldehydes with -hydrogens are able to form a single aldol condensation product. B) Two different ketones with -hydrogens are able to form a single aldol condensation product. C) Any aldehyde and ketone mixed together can react to form a single condensation product.

Page 11

Chapter 24: Carbonyl Condensation Reactions

Answer Key 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44.

B C A D B D A C A D B B A D B C A C A B D D C B C A D B D D B B A B C B D A D A A A C C

Page 12

Chapter 24: Carbonyl Condensation Reactions

45. D

Page 13...