Deck 22: Carbonyl Condensation Reactions

Question 1

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
C)Enolate formation,nucleophilic addition,protonation
D)Nucleophilic addition,enolate formation,protonation

Answer 1

Enolate formation,nucleophilic addition,protonation

Question 2

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

A)I
B)II
C)III
D)IV

Answer 2

I

Question 3

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

A)I
B)II
C)III
D)IV

Answer 3

III

Question 4

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

A)a-Hydroxy carbonyl compound
B)b-Hydroxy carbonyl compound
C)g-Hydroxy carbonyl compound
D)a,b-Hydroxy carbonyl compound

Question 5

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

A)I
B)II
C)III
D)IV

Question 6

What reaction type is an Aldol reaction?

A)Nucleophilic substitution
B)Electrophilic substitution
C)Electrophilic addition
D)Nucleophilic addition

Question 7

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

A)I
B)II
C)III
D)None of the choices

Question 8

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

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.

Question 9

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

A)I
B)II
C)III
D)IV

Question 10

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

A)I
B)II
C)III
D)IV

Question 11

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

A)I
B)II
C)I and II
D)None of the choices

Question 12

What is the general name for the reaction product formed in a Claisen reaction?

A)b-Hydroxy ester
B)b-Keto ester
C)a-Keto ester
D)g-Hydroxy ester

Question 13

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

A)I
B)II
C)III
D)IV

Question 14

What is the name given to an Aldol reaction between two different carbonyl compounds?

A)Multiple Aldol reaction
B)Crossed Aldol reaction
C)Differential Aldol reaction
D)Versatile Aldol reaction

Question 15

Which is the unsaturated carbonyl compound formed in the dehydration of the following b-hydroxy carbonyl compound?

A)I
B)II
C)I and II
D)None of the choices

Question 16

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

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

Question 17

Why is the Aldol reaction often called an Aldol condensation?

A)The initially formed b-hydroxy carbonyl compound loses a hydroxyl group.
B)The initially formed b-hydroxy carbonyl compound loses an oxygen atom.
C)The initially formed b-hydroxy carbonyl compound loses a hydrogen atom.
D)The initially formed b-hydroxy carbonyl compound loses water.

Question 18

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

A)I
B)II
C)III
D)IV

Question 19

What is the general name for the class of products formed in an Aldol condensation reaction?

A)b,g-Unsaturated carbonyl compound
B)a,b-Unsaturated carbonyl compound
C)a,g-Unsaturated carbonyl compound
D)b-Hydroxy carbonyl compound

Question 20

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

A)When both carbonyl compounds have a hydrogens
B)When both carbonyl compounds have no a hydrogens
C)When one carbonyl compound has no a hydrogens
D)When one carbonyl compound has no b hydrogens

Question 21

What is the name given to the Claisen reaction between two different esters?

A)Multiple Claisen reaction
B)Differential Claisen reaction
C)Crossed Claisen reaction
D)Versatile Claisen reaction

Question 22

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

A)Enolate formation,elimination,nucleophilic addition
B)Enolate formation,nucleophilic addition,elimination
C)Elimination,enolate formation,nucleophilic addition
D)Nucleophilic addition,enolate formation,elimination

Question 23

What is the product of the following Claisen reaction?

A)I
B)II
C)III
D)IV

Question 24

In a Michael reaction,what is the name given to the a,b-unsaturated carbonyl component?

A)Michael donor
B)Michael enolate
C)Michael nucleophile
D)Michael acceptor

Question 25

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

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.

Question 26

What reaction type is a Claisen reaction?

A)Electrophilic addition
B)Electrophilic substitution
C)Nucleophilic addition
D)Nucleophilic substitution

Question 27

What are the names for the two parts of the mechanism in a Robinson annulation?

A)Michael addition and intramolecular Claisen reaction
B)Michael addition and intramolecular aldol reaction
C)Claisen reaction and intramolecular aldol reaction
D)Aldol reaction and intramolecular Claisen reaction

Question 28

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

A)I
B)II
C)III
D)IV

Question 29

What is the product of the following Claisen reaction?

A)I
B)II
C)III
D)IV

Question 30

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

A)I
B)II
C)III
D)IV

Question 31

Which of the following compounds can undergo an Aldol with itself?

A)I
B)II
C)III
D)Both I and II

Question 32

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

A)b-Keto ester
B)a,b-Dicarbonyl compound
C)g-Dicarbonyl compound
D)b-Dicarbonyl compound

Question 33

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

A)Michael reaction
B)Aldol self-condensation
C)Dieckmann condensation
D)Robinson annulation

Question 34

What are the two starting materials for a Robinson annulation?

A)an a,b-Unsaturated carbonyl compound and an enolate
B)a b-Ketoester and an enolate
C)a 1,5-Dicarbonyl compound and an enolate
D)a 1,3-Dicarbonyl compound and an enolate

Question 35

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

A)Claisen condensation
B)Mixed Aldol reaction
C)Robinson annulation
D)Dieckmann condensation

Question 36

The b-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.
D)Hydroxide is eliminated via an enolate intermediate.

Question 37

What is an intramolecular Claisen reaction called?

A)Michael reaction
B)Robinson reaction
C)Hoffman reaction
D)Dieckmann reaction

Question 38

What type of esters can undergo Claisen reactions?

A)All esters can undergo Claisen reactions.
B)Only esters with two hydrogen atoms on the a carbon can undergo Claisen reactions.
C)Only esters with three hydrogen atoms on the a carbon can undergo Claisen reactions.
D)Only esters with two or three hydrogen atoms on the a carbon can undergo Claisen reactions.

Question 39

When is a crossed Claisen reaction between two different esters synthetically useful?

A)When only one of the esters has a hydrogen atoms
B)When both esters have a hydrogen atoms
C)When only one of the esters has b hydrogen atoms
D)When both esters lack a hydrogen atoms

Question 40

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

A)a-Carbon
B)b-Carbon
C)Carbonyl carbon
D)Carbonyl carbon and b-carbon

Question 41

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV

Question 42

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 a-hydrogens are able to form a single aldol condensation product.
B)Two different ketones with a-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.
D)Any pair of aldehyde or ketone reactants where one of the reactants has no a-hydrogens will lead to a single aldol product.

Question 43

What product (including stereochemistry)is formed in the following intermolecular reaction?

A)I
B)II
C)III
D)IV

Question 44

Of the carbonyl compounds; (1)benzaldehyde,(2)acetophenone and (3)dicyclohexyl ketone,which compound has noa-hydrogens?

A)Benzaldehyde
B)Acetophenone
C)Acetone
D)All of these compounds contain a-hydrogens.

Question 45

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV

Question 46

Which of the following bicyclic ring systems can be prepared by an intermolecular Robinson annulation?

A)I
B)II
C)III
D)IV

Question 47

What product (including stereochemistry)is formed in the following intermolecular reaction?

A)I
B)II
C)III
D)IV

Question 48

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

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.

Question 49

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.
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.

Question 50

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV

Question 51

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.
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.