Question 1

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

Accepted Answer

A)   The electrophilic carbonyl component is relatively unhindered and is used in excess.
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.E) A) and B)
F) C) and D)

Question 2

When is a crossed Aldol reaction said to be synthetically useful?

Accepted Answer

A)   When both carbonyl compounds have  hydrogens.
B)   When both carbonyl compounds have no  hydrogens.
C)   When one carbonyl compound has no  hydrogens.
D)   When one carbonyl compound has no  hydrogens.E) A) and C)
F) All of the above

Question 3

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

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and C)
F) B) and D)

Question 4

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

Accepted Answer

A)   I
B)   II
C)   III
D)   None of the choicesE) A) and B)
F) A) and C)

Question 5

In the correct order, what are the three general steps in the mechanism of a Claisen reaction?

Accepted Answer

A)   Enolate formation, elimination, nucleophilic addition.
B)   Enolate formation, nucleophilic addition, elimination.
C)   Elimination, enolate formation, nucleophilic addition.
D)   Nucleophilic addition, enolate formation, elimination.E) None of the above
F) A) and B)

Question 6

In a Michael reaction, where does the nucleophile attack the ,-unsaturated carbonyl component?

Accepted Answer

A)   "-Carbon"
B)   "-Carbon"
C)   "Carbonyl carbon"
D)   "Carbonyl carbon and -carbon"E) A) and B)
F) All of the above

Question 7

What is the general name for the reaction product formed in an aldol addition reaction?

Accepted Answer

A)   "-hydroxy carbonyl compound."
B)   "-hydroxy carbonyl compound."
C)   "-hydroxy carbonyl compound."
D)   ",-hydroxy carbonyl compound."E) B) and C)
F) All of the above

Question 8

Which of the following compounds cannot serve as a Michael acceptor?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) B) and C)
F) A) and D)

Question 9

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

Accepted Answer

A)   Claisen condensation
B)   mixed Aldol reaction
C)   Robinson annulation
D)   Dieckmann condensationE) All of the above
F) C) and D)

Question 10

Would this crossed Aldol reaction work well? Why or why not?

Accepted Answer

A)   Yes, the diketone is significantly more acidic, so this enolate can be formed selectively.
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.E) A) and B)
F) A) and C)

Question 11

What are the two starting materials for a Robinson annulation?

Accepted Answer

A)   an ,-unsaturated carbonyl compound and an enolate
B)   a -ketoester and an enolate
C)   a 1,5-dicarbonyl compound and an enolate
D)   a 1,3-dicarbonyl compound and an enolateE) A) and C)
F) B) and C)

Question 12

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?

Accepted Answer

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.
C)   Transesterfication can occur when esters react, and this transesterfication would result in a mixture of products.
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.E) B) and D)
F) B) and C)

Question 13

Which is the unsaturated carbonyl compound is formed by the dehydration of the following -hydroxy carbonyl compound? -hydroxy carbonyl compound?   A)  I B)  II C)  I and II D)  None of the choices" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   I
B)   II
C)   I and II
D)   None of the choicesE) A) and C)
F) B) and D)

Question 14

Complete this statement: A major difference between the Aldol condensation and the Claisen condensation reactions is that

Accepted Answer

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.
C)   the Aldol reaction is base catalyzed while the Claisen reaction requires a full equivalent of base.
D)   the Aldol reaction is base catalyzed while the Claisen reaction is acid-catalyzed.E) B) and C)
F) None of the above C

Question 15

Why is the Aldol reaction often called an Aldol condensation?

Accepted Answer

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.
D)   The initially formed -hydroxy carbonyl compound loses water.E) A) and B)
F) A) and D)

Question 16

What reaction type is an Aldol reaction?

Accepted Answer

A)   nucleophilic substitution
B)   electrophilic substitution
C)   electrophilic addition
D)   nucleophilic additionE) A) and D)
F) A) and C) D

Question 17

What is the Aldol addition product formed from the reaction of (CH3) 2CHCH2CHO with itself? 3) 2CHCH2CHO with itself?   A)  I B)  II C)  III D)  IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) None of the above
F) All of the above D

Question 18

What is the general name of the product of a crossed Claisen reaction between a ketone and an ester?

Accepted Answer

A)   "-keto ester"
B)   ",-dicarbonyl compound"
C)   "-dicarbonyl compound"
D)   "-dicarbonyl compound"E) A) and B)
F) All of the above

Question 19

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

Accepted Answer

A)   The initial Aldol product is an alkoxide, so the reaction is not energetically downhill in either direction.
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.E) A) and B)
F) A) and C)

Question 20

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

Accepted Answer

A)   Michael reaction
B)   Aldol self-condensation
C)   Dieckmann condensation
D)   Robinson annulationE) B) and C)
F) A) and D)

Exam 24: Carbonyl Condensation Reactions

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

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When is a crossed Aldol reaction said to be synthetically useful?

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

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

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In the correct order, what are the three general steps in the mechanism of a Claisen reaction?

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In a Michael reaction, where does the nucleophile attack the ,-unsaturated carbonyl component?

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What is the general name for the reaction product formed in an aldol addition reaction?

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Which of the following compounds cannot serve as a Michael acceptor?

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

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Would this crossed Aldol reaction work well? Why or why not?

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What are the two starting materials for a Robinson annulation?

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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?

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Which is the unsaturated carbonyl compound is formed by the dehydration of the following -hydroxy carbonyl compound?

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Complete this statement: A major difference between the Aldol condensation and the Claisen condensation reactions is that

Correct AnswerverifiedC

Why is the Aldol reaction often called an Aldol condensation?

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What reaction type is an Aldol reaction?

Correct AnswerverifiedD

What is the Aldol addition product formed from the reaction of (CH3) 2CHCH2CHO with itself?

Correct AnswerverifiedD

What is the general name of the product of a crossed Claisen reaction between a ketone and an ester?

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

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

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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?

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C

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D

What is the Aldol addition product formed from the reaction of (CH₃) ₂CHCH₂CHO with itself?

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D

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