Deck 17: Carbonyl Alpha-Substitution and Condensation Reactions

Question 1

Which of the following is common to both tautomers and resonance forms of a compound?

A) have the same molecular formula
B) differ only in the position of electrons
C) rapidly interconvertible
D) differ in connectivity of atoms
E) all of these describe both tautomers and resonance forms

Answer 1

have the same molecular formula

Question 2

Consider the reaction sequence below to answer the following question(s).
Refer to instructions. Conversion of A into B is a type of reaction termed _____.

A) an acylation
B) an enolation
C) an alkylation
D) a phenylation

Answer 2

an alkylation

Question 3

Refer to the compounds below to answer the following question(s).
Refer to instructions. Draw the structure for the enol and enolate ions corresponding to Compound I.

Answer 3

Question 4

The common feature of α-substitution and condensation reactions of carbonyl groups:

A) involve two carbonyl partners
B) involve the formation of an enol or enolate ion
C) involve a nucleophile
D) produce a new carbon to carbon bond
E) all of these describe both types of reactions

Question 5

Give the major organic product(s) of each reaction or sequences of reactions for the following question(s). Show all relevant stereochemistry.
Give major product(s):

Question 6

Refer to the compounds below to answer the following question(s).
Refer to instructions. Indicate which hydrogens in Compound II are the most acidic. Explain your answer.

Question 7

Which of the following would form an enolate ion on treatment with a base?

A) A
B) B
C) C
D) D
E) All of these except C

Question 8

Give the major organic product(s) of each reaction or sequences of reactions for the following question(s). Show all relevant stereochemistry.
How would you prepare 3-phenylpropanoic acid using a malonic ester synthesis?

Question 9

Refer to the compounds below to answer the following question(s).
Refer to instructions. Choose the most acidic compound from Compounds I − IV. Explain your choice.

Question 10

An enolate ion

A) is a resonance hybrid.
B) can be protonated to from the corresponding enol.
C) can be protonated to form the keto tautomer.
D) forms under basic conditions.
E) All of these

Question 11

Give the major organic product(s) of each reaction or sequences of reactions for the following question(s). Show all relevant stereochemistry.
How would you prepare 5-methyl-2-hexanone using an acetoacetic ester synthesis?

Question 12

Give the major organic product(s) of each reaction or sequences of reactions for the following question(s). Show all relevant stereochemistry.
Give major product(s):

Question 13

Consider the structures below to answer the following question(s).
Refer to instructions. Underline the most acidic hydrogen atoms in each of the molecules.

Question 14

Consider the structures below to answer the following question(s).
Nitroethane [CH₃CH₂NO₂, pK_a = 8.6] is a much stronger acid than ethane [CH₃CH₃, pK_a ≈ 60]. Explain.

Question 15

Which of the following would form an enol on treatment with an acid?

A) 4-chlorobenzaldehye
B) 2,2,-dimethylbutanal
C) 2,2,4,4-tetrachlorohexan-3-one
D) none of these

Question 16

Give the major organic product(s) of each reaction or sequences of reactions for the following question(s). Show all relevant stereochemistry.
Refer to instructions.
a)Give major product(s): b)Why are two equivalents of Na⁺ OEt− required?

Question 17

Consider the structures below to answer the following question(s).
Refer to instructions. Rank the molecules above in order of increasing acidity (least acidic to most acidic).

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

Question 18

Refer to the compounds below to answer the following question(s).
Refer to instructions. Underline all the acidic hydrogen atoms in Compounds I through IV.

Question 19

Consider the reaction sequence below to answer the following question(s).
Refer to instructions. The starting material A in this reaction sequence is called a(n) _____.

A) β-keto ester
B) α-carboethoxy ketone
C) malonic ester
D) acetoacetic ester

Question 20

Consider the reaction sequence below to answer the following question(s).
Refer to instructions. Conversion of B into C involves hydrolysis of the ester followed by decarboxylation. On the structures provided below, show the electron flow for the decarboxylation step.

Question 21

Draw the structures of the precursors to the Michael reaction products shown in the question(s) below. Label the Michael donor and the Michael acceptor in each case and formulate the reaction.
Draw and label:

Question 22

Draw the structures of the precursors to the Michael reaction products shown in the question(s) below. Label the Michael donor and the Michael acceptor in each case and formulate the reaction.
Draw and label:

Question 23

Draw the structure of the product you would expect to obtain by Claisen condensation of the esters shown in the question(s) below. If an ester does not undergo Claisen condensation, explain why it does not.
Draw and explain:

Question 24

Each of the following compounds in the following question(s) can be prepared by a mixed aldol condensation reaction.a)
Give the structures of the aldehyde and/or ketone precursors for each aldol condensation product and formulate the reaction.b)
Give the structure of the intermediate aldol product.
Refer to instructions. Use the following compound:

Question 25

Draw the structure of the aldol self-condensation product of each compound for the following question(s). If a compound does not undergo aldol self-condensation, explain why it does not.
Draw and explain:

Question 26

Consider the reaction below to answer the following question(s).
Refer to instructions. Write the complete stepwise mechanism for the reaction above. Show all intermediate structures and all electron flow with arrows.

Question 27

Each of the following compounds in the following question(s) can be prepared by a mixed aldol condensation reaction.a)
Give the structures of the aldehyde and/or ketone precursors for each aldol condensation product and formulate the reaction.b)
Give the structure of the intermediate aldol product.
Refer to instructions. Use the following compound:

Question 28

Draw the structure of the aldol self-condensation product of each compound for the following question(s). If a compound does not undergo aldol self-condensation, explain why it does not.
Draw and explain:

Question 29

Consider the reaction below to answer the following question(s).
Refer to instructions. Draw the structure of the enolate ion that is generated during the course of this reaction.

Question 30

Consider the reaction below to answer the following question(s).
Refer to instructions. Which carbonyl compound functions as the electrophile in this reaction?

A)A
B)B
C)C

Question 31

Draw the structure of the aldol self-condensation product of each compound for the following question(s). If a compound does not undergo aldol self-condensation, explain why it does not.
Draw and explain:

Question 32

Draw the structures of the precursors to the Michael reaction products shown in the question(s) below. Label the Michael donor and the Michael acceptor in each case and formulate the reaction.
Draw and label:

Question 33

Consider the reaction below to answer the following question(s).
Refer to instructions. The product of this reaction is:

A) a β, γ-unsaturated aldehyde
B) an α, β-unsaturated ketone
C) an α, β-unsaturated aldehyde
D) an enol

Question 34

Consider the reaction below to answer the following question(s).
Refer to instructions. This reaction is an example of:

A) an intramolecular Claisen condensation
B) an intramolecular aldol condensation
C) a Robinson annulation
D) a Michael reaction

Question 35

Consider the reaction below to answer the following question(s).
Refer to instructions. This reaction is an example of:

A) a mixed Claisen condensation.
B) a Dieckman condensation.
C) a Michael reaction.
D) a mixed aldol reaction.

Question 36

Draw the structure of the product you would expect to obtain by Claisen condensation of the esters shown in the question(s) below. If an ester does not undergo Claisen condensation, explain why it does not.
Draw and explain:

Question 37

Which of the following does not possess an enol form? Explain your choice.

Question 38

The Stork enamine reaction is a variation on the Michael reaction that utilizes an enamine nucleophile. Use this information to answer the following question.
Refer to instructions. Draw the structures of the ketone and amine products of this reaction.

Question 39

Rank the following hydrogens in terms of decreasing acidity (most acidic > least acidic):

Question 40

Each of the following compounds in the following question(s) can be prepared by a mixed aldol condensation reaction.a)
Give the structures of the aldehyde and/or ketone precursors for each aldol condensation product and formulate the reaction.b)
Give the structure of the intermediate aldol product.
Refer to instructions. Use the following compound:

Question 41

How would you prepare the following compound using an alkylation reaction?

Question 42

Identify products a and
b.

Question 43

Predict the major aldol product of the following reaction.

Question 44

Identify the intermediate imine that results from the following reaction.

Question 45

When treated with base and heat, the following diketone undergoes an intramolecular aldol reaction followed by dehydration to produce cis-jasmone, a perfume component. Draw the structure of the product.

Question 46

Draw the structure of the diastereomer that is formed preferentially in the following reaction: