Deck 19: Carbonyl Chemistry 2: Reactions at the Α Position

Question 1

Which of the following could not serve as a starting material in the synthesis of the following material?

A)
B)
C)
D)
E)

Answer 1

Question 2

Which of the following compounds is the weakest acid?

A)
B)
C)
D)
E)

Answer 2

Question 3

Which of the following is the correct product of the reaction sequence shown?

A)
B)
C)
D)
E)

Answer 3

Question 4

Which of the following compounds could not be used as a substrate for an alkylation reaction with a ketone enolate?

A)
B)
C)
D)
E)

Question 5

Rank the circled protons in the following compounds from least acidic to most acidic:

A)
B)
C)
D)
E)

Question 6

Why is the carbon atom typically the nucleophilic site of an enolate anion?

A)Most of the negative charge resides on the carbon atom.
B)The resonance form with the negative charge on carbon is the major contributor.
C)The alkoxy anion will not act as a Lewis base, due to oxygen electronegativity.
D)The HOMO of the enolate has its largest lobe at the beta-carbon.
E)The bonding MO of the enolate has its highest electron density around the oxygen.

Question 7

Which of the following is the correct product of the reaction conditions shown?

A)
B)
C)
D)
E)

Question 8

Why should lithium diisopropylamide (LDA) be used in enolate alkylation reactions?

A)LDA completely converts one equivalent of carbonyl to enolate.
B)LDA is too bulky to act as a nucleophile.
C)Lithium complexation with the enolate oxygen can reduce O-alkylation.
D)LDA will selectively remove the least hindered protons from the carbonyl.
E)All these reasons are valid.

Question 9

What is the final product of the following reaction sequence?

A)
B)
C)
D)
E)

Question 10

Which of the following structures will have the greatest amount of enol content at equilibrium?

A)
B)
C)
D)
E)

Question 11

Which of the following is the correct product of the reaction conditions shown?

A)
B)
C)
D)
E)

Question 12

What is the final product of the following reaction sequence?

A)
B)
C)
D)
E)

Question 13

What is the product of the following transformation?

A)
B)
C)
D)
E) Either a or b is possible.

Question 14

What are the starting materials needed to make the molecule shown using an aldol condensation?

A)
B)
C)
D)
E)

Question 15

What would be the expected product of the following synthetic sequence?

A)
B)
C)
D)
E)

Question 16

What is the product of the reaction conditions shown?

A)
B)
C)
D)
E)

Question 17

What is the final product of this reaction sequence?

A)
B)
C)
D)
E)

Question 18

Predict the major organic product of the following reaction.

A)
B)
C)
D)
E)

Question 19

Which of the following is the correct product of the conditions shown?

A)
B)
C)
D)
E)

Question 20

What is the product of this reaction?

A)
B)
C)
D)
E)

Question 21

Which of the following is a thermodynamic enolate?

A)
B)
C)
D)
E)

Question 22

In aqueous base, the chiral ketone shown here racemizes.Provide an explanation.

Question 23

What is the product of this reaction?

A)
B)
C)
D)
E)

Question 24

Which of these structures is the product of the reaction?

A)
B)
C)
D)
E) None of these structures is the product of the reaction.

Question 25

Provide a mechanism for the following transformation.

Question 26

Which of these compounds is the stronger acid? Explain your reasoning.

Question 27

Which of the following would be products of the following crossed aldol condensation reaction?

A)
B)
C)
D)
E) All would be products

Question 28

What would be the product of the following reaction sequence?

A)
B)
C)
D)
E)

Question 29

What is the product of the following reaction sequence?

A)
B)
C)
D)
E)

Question 30

What is the product of the following reaction sequence?

A)
B)
C)
D)
E)

Question 31

Which of the following compounds cannot undergo a Dieckmann condensation?

A)
B)
C)
D)
E)

Question 32

Which of the following is a mechanistic intermediate in this Mannich reaction?

A)
B)
C)
D)
E)

Question 33

Which of the following esters cannot undergo a successful Claisen condensation?

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

Question 34

Provide a mechanism for the following transformation.

Question 35

What is the product of the following reaction conditions?

A)
B)
C)
D)
E) None of these is the product of the conditions shown.

Question 36

What is the product of the reaction conditions shown?

A)
B)
C)
D)
E) None of these structures is the product of the reaction conditions shown.

Question 37

Which of these compounds could reasonably form under the reaction conditions?

A)
B)
C)
D)
E)

Question 38

What is the product of this reaction?

A)
B)
C)
D)
E)

Question 39

What is the product of the reaction conditions shown?

A)
B)
C)
D)
E)

Question 40

Provide a mechanism for the following transformation.

Question 41

Predict the product of the reaction sequence shown.

Question 42

Draw a mechanism for the following transformation.Include all necessary lone pairs of electrons,
curved arrows, and nonzero formal charges.

Question 43

Predict the product of the following reaction sequence and draw a mechanism to rationalize its
formation.Include all necessary lone pairs of electrons, curved arrows, and nonzero formal
charges.

Question 44

Halogenation at the α position of carbonyls can be performed in acidic or basic conditions, but
with different results.In acidic conditions, the reaction stops at the monohalogenated product, but
under basic conditions, additional halogenations occur.Explain.

Question 45

What is the product of the following reaction?

Question 46

Draw the product of the following reaction.

Question 47

Devise a multistep synthesis for the following transformation.Show the reagents needed for each
step and the product of each step.Do not draw any mechanisms.

Question 48

Predict the product of the following transformation and draw a mechanism to rationalize its
formation.Include all necessary lone pairs of electrons, curved arrows, and nonzero formal
charges.

Question 49

Devise a multistep synthesis for the following transformation.Show the reagents needed for each
step and the product of each step.Do not draw any mechanisms.

Question 50

Draw a mechanism for the following transformation.Include all necessary lone pairs of electrons,
curved arrows, and nonzero formal charges.

Question 51

Draw the product from the following synthesis.

Question 52

Draw a mechanism to illustrate the transformation shown here.Include all necessary lone pairs of
electrons, curved arrows, and nonzero formal charges.

Question 53

Devise a multistep synthesis for the following transformation.Show the reagents needed for each
step and the product of each step.Do not draw any mechanisms.

Question 54

Draw a mechanism for the transformation shown here. Include all necessary lone pairs of electrons, curved arrows, and nonzero formal charges.

Question 55

Draw a mechanism for the transformation shown here.Include any necessary lone pairs of
electrons, curved arrows, and nonzero formal charges.

Question 56

Show the principal product(s) of the following reaction:

Question 57

Devise a multistep synthesis for the following transformation.Show the reagents needed for each
step and the product of each step.Do not draw any mechanisms.

Question 58

Predict the product of the following reaction.

Question 59

Draw the intermediates and final product in the synthetic sequence shown.

Question 60

Devise a multistep synthesis for the following transformation.Show the reagents needed for each
step and the product of each step.Do not draw any mechanisms.

Question 61

Devise a multistep synthesis for the following transformation. Show the reagents needed for each step and the product of each step. Do not draw any mechanisms.

Question 62

Design a multistep synthesis of the target molecule from the indicated starting material.Show the
reagents needed for each step and the product of each step.Do not show any mechanisms.

Question 63

Draw the product of the following reaction.

Question 64

Provide the missing reagents in the following reaction sequence.

Question 65

Devise a multistep synthesis for the following transformation. Show the reagents needed for each step and the product of each step. Do not draw any mechanisms.

Question 66

The ester shown here cannot undergo a successful Claisen condensation.Explain why.

Question 67

Show the mechanism of the following reaction.

Question 68

Draw the principal product in the following synthesis.

Question 69

Show the mechanism of the reaction that acetone undergoes in the presence of aqueous base.

Question 70

Draw the structures of the starting materials and any reagents necessary to synthesize this
compound using a Claisen condensation.

Question 71

Design a multistep synthesis of the target molecule from the indicated starting material.Show the
reagents needed for each step and the product of each step.Do not show any mechanisms.