Question 1

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?

Accepted Answer

A)   Two different aldehydes with a-hydrogens are able to form a single aldol condensation product.
B)   Any pair of aldehyde or ketone reactants where one of the reactants has no a-hydrogens will lead to a single aldol product.
C)   Two different ketones with a-hydrogens are able to form a single aldol condensation product.
D)   Any aldehyde and ketone mixed together can react to form a single condensation product.E) C) and D)
F) B) and D)

Question 2

What is the major product of the following reaction?

Accepted Answer

A)   II
B)   IV
C)   III
D)   IE) B) and D)
F) C) and D)

Question 3

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 weaker base than NaOCH2CH3, and this reaction requires a weaker base.
B)   Transesterfication can occur when esters react, and this transesterfication would result in a mixture of products.
C)   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.
D)   NaOCH3 is a stronger base than NaOCH2CH3, and this reaction requires a stronger base.E) A) and C)
F) C) and D)

Question 4

What is the major product of the following reaction?

Accepted Answer

A)   II
B)   IV
C)   I
D)   IIIE) A) and D)
F) B) and D) A

Question 5

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 nucleophilic carbonyl component is relatively unhindered and is used in excess.
C)   The electrophilic carbonyl carbon component is relatively hindered and is used in limited amount.
D)   The nucleophilic carbonyl component is relatively hindered and is used in limited amount.E) B) and D)
F) All of the above

Question 6

What is the major product of the following reaction?

Accepted Answer

A)   IV
B)   II
C)   III
D)   IE) B) and C)
F) A) and B)

Question 7

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

Accepted Answer

A)   Dieckmann condensation
B)   Robinson annulation
C)   Aldol self-condensation
D)   Michael reactionE) A) and B)
F) A) and D)

Question 8

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

Accepted Answer

A)   the Aldol reaction is base catalyzed while the Claisen reaction is acid-catalyzed.
B)   the Aldol reaction is base catalyzed while the Claisen reaction requires a full equivalent of base.
C)   the Aldol reaction involves substitution while the Claisen reaction involves addition.
D)   the Aldol reaction is acid catalyzed while the Claisen reaction is base-catalyzed.E) B) and D)
F) A) and B) B

Question 9

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

Accepted Answer

A)   No, the aldehyde is significantly more acidic, so this enolate cannot be formed selectively.
B)   No, the diketone is significantly more acidic, so this enolate cannot be formed selectively.
C)   Yes, the diketone is significantly more acidic, so this enolate can be formed selectively.
D)   Yes, the aldehyde is significantly more acidic, so this enolate can be formed selectively.E) A) and C)
F) A) and B)

Question 10

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 energetically downhill going toward the product.
B)   The initial Aldol product is an alkoxide, so the reaction is energetically downhill going toward the starting materials.
C)   Water is a stable molecule.
D)   The initial Aldol product is an alkoxide, so the reaction is not energetically downhill in either direction.E) A) and C)
F) B) and D)

Question 11

The b-hydroxy carbonyl product of an Aldol reaction is oftentimes not the final isolated product; what is the explanation for this result?

Accepted Answer

A)   The hydroxy group reacts with the carbonyl to form a ketal.
B)   The hydroxy group is oxidized to a carbonyl.
C)   Hydroxide is eliminated via an enolate intermediate.
D)   It undergoes elimination, since water is a good leaving group.E) None of the above
F) A) and C)

Question 12

Which of the following statements about Aldol reactions with either aldehydes or ketones is true?

Accepted Answer

A)   Equilibrium favors the products with aldehydes; equilibrium favors the starting materials with ketones.
B)   Equilibrium favors the starting materials with aldehydes; equilibrium favors the products with ketones.
C)   Equilibrium favors the starting materials with both aldehydes and ketones.
D)   Equilibrium favors the products with both aldehydes and ketones.E) None of the above
F) C) and D)

Question 13

A key step in the biosynthesis of glucose involves the reaction of glyceraldehyde 3-phosphate with dihydroxyacetone phosphate to form fructose 1,6-bisphosphate in the presence of an aldolase enzyme. The end product formed from this reaction is

Accepted Answer

A)   a single form of fructose in the cyclic hemiacetal form.
B)   a form of critic acid.
C)   a single form of fructose in the acyclic form.
D)   an equilibrium between an acyclic form of fructose and a cyclic hemiacetal.E) C) and D)
F) A) and C) D

Exam 17: Carbonyl Condensation Reactions

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?

Correct Answer
verified

What is the major product of the following reaction?

Correct Answer
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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?

Correct Answer
verified

What is the major product of the following reaction?

Correct Answer
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A

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

Correct Answer
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What is the major product of the following reaction?

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

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

Correct Answer
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B

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

Correct Answer
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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?

Correct Answer
verified

The b-hydroxy carbonyl product of an Aldol reaction is oftentimes not the final isolated product; what is the explanation for this result?

Correct Answer
verified

Which of the following statements about Aldol reactions with either aldehydes or ketones is true?

Correct Answer
verified

A key step in the biosynthesis of glucose involves the reaction of glyceraldehyde 3-phosphate with dihydroxyacetone phosphate to form fructose 1,6-bisphosphate in the presence of an aldolase enzyme. The end product formed from this reaction is

Correct Answer
verified
D

Exam 17: Carbonyl Condensation Reactions

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?

Correct AnswerverifiedShow Answer

What is the major product of the following reaction?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

What is the major product of the following reaction?

Correct AnswerverifiedA

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

Correct AnswerverifiedShow Answer

What is the major product of the following reaction?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedB

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The b-hydroxy carbonyl product of an Aldol reaction is oftentimes not the final isolated product; what is the explanation for this result?

Correct AnswerverifiedShow Answer

Which of the following statements about Aldol reactions with either aldehydes or ketones is true?

Correct AnswerverifiedShow Answer

A key step in the biosynthesis of glucose involves the reaction of glyceraldehyde 3-phosphate with dihydroxyacetone phosphate to form fructose 1,6-bisphosphate in the presence of an aldolase enzyme. The end product formed from this reaction is

Correct AnswerverifiedD

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Correct Answer
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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?

Correct Answer
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Correct Answer
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A

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B

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D