Deck 27: Reactions Involving Free Radicals

Question 1

Which of the following reactions will not result in a racemic mixture of products?

A)
B)
C)
D)
E)

Answer 1

Question 2

Which of the following is a propagation step that would lead to the product shown in the reaction below?

A)
B)
C)
D)
E)

Answer 2

Question 3

Which of the following reactions would not result in a racemic mixture of products?

A)
B)
C)
D)
E)

Answer 3

Question 4

Which of the following is an intermediate in the reaction below?

A)
B)
C)
D)
E)

Question 5

Which of the following does not contain a carbon atom that is sp² hybridized?

A)
B)
C)
D)
E)

Question 6

What is the rate-determining step in the reaction below?

A)Proton transfer
B)Electrophilic addition
C)Radical coupling
D)Radical addition
E)Bimolecular homolytic substitution

Question 7

What type of elementary step is shown below?

A)Radical coupling
B)Homolytic bond cleavage
C)Bimolecular homolytic substitution
D)Radical addition
E)Radical halogenation

Question 8

Which of the following would result in the most stable product after homolytic cleavage of the C-Br bond?

A)
B)
C)
D)
E)

Question 9

How many different radical species could be produced from homolysis of a C-H bond in the molecule below?

A)Two
B)Three
C)Four
D)Five
E)Six

Question 10

Which of the following will undergo C-Cl bond homolysis at the highest rate?

A)
B)
C)
D)
E)

Question 11

Which of the following elementary steps does not occur in the reaction below?

A)Bond homolysis
B)Electrophilic addition
C)Radical addition
D)Bimolecular homolytic substitution
E)All of these steps occur in the reaction shown.

Question 12

Which of the following is true regarding the reaction shown below?

A)When X = Cl, the reaction will occur at a higher rate and will result in a lower ratio of Product A to Product B than when X = Br.
B)When X = Br, the reaction will occur at a higher rate and will result in a higher ratio of Product A to Product B than when X = Cl.
C)When X = Cl, the reaction will occur at a lower rate and will result in a lower ratio of Product A to Product B than when X = Br.
D)When X = Br, the reaction will occur at a lower rate and will result in a lower ratio of Product A to Product B than when X = Cl.
E)When X = Cl, the reaction will occur at a lower rate and will result in a higher ratio of Product A to Product B than when X = Br.

Question 13

Which of the following steps is most endothermic?

A)
B)
C)
D)
E)All of these steps are equally endothermic.

Question 14

Predict the major products of homolytic C-C bond cleavage in the molecule below.

A)
B)
C)
D)
E)

Question 15

Which of the following C-C bonds is the weakest?

A)A
B)B
C)C
D)D
E)E

Question 16

Which of the following is a termination step that could occur in the reaction below?

A)
B)
C)
D)
E)

Question 17

Predict the major product of the reaction below.

A)
B)
C)
D)
E)

Question 18

What product other than the ones shown could be formed in the radical halogenation reaction below?

A)
B)
C)
D)
E)

Question 19

What is the first elementary step that occurs in the mechanism of the reaction shown below?

A)Radical halogenation
B)Radical addition
C)Bimolecular homolytic substitution
D)Bond homolysis
E)Radical coupling

Question 20

Which of the following free radicals is the least stable?

A)
B)
C)
D)
E)

Question 21

Draw two additional resonance structures for the species shown below,and draw arrows to show the conversion between resonance structures.

Question 22

Draw two resonance structures of the radical species below.Include curved arrows.

Question 23

Draw the two products most likely to result from C-C bond homolysis of the molecule below,and draw single-barbed arrows showing the formation of these products.

Question 24

Predict the major product of the reaction below,and draw a detailed mechanism for the production of Br₂ from NBS as it would occur in this reaction.

Question 25

Draw two products that could be formed in the following radical addition step.

Question 26

Indicate where the weakest C-H bond is in the molecule below.

Question 27

Draw the product of the radical addition below,and add curved arrows to show the movement of electrons.

Question 28

Predict the product of the following reaction.

A)
B)
C)
D)
E)

Question 29

Predict the major product of the reaction below,and draw complete mechanisms for the initiation and propagation steps.

Question 30

Draw a reasonable mechanism for the fragmentation reaction shown below.

Question 31

What is the missing starting material for the following reaction sequence?

A)
B)
C)
D)
E)

Question 32

Draw the mechanism for the reaction below.Label the initiation step and the propagation steps,and include two plausible termination steps.

Question 33

What starting material is missing from the reaction scheme below?

A)
B)
C)
D)
E)

Question 34

The following intermediate undergoes an intramolecular radical addition reaction,yielding a product that contains a secondary alkyl radical.Draw a mechanism for this reaction,and predict the structure of the product.

Question 35

Fill in the missing product and draw single-barbed arrows to show the movement of electrons in the reaction below.

Question 36

Draw all possible products from homolytic C-H bond cleavage in the molecule below,and indicate which product would be most stable.

Question 37

Fill in the missing reactant in the following mechanism step.

Question 38

Which of the following will undergo a Birch reduction at the highest rate?

A)
B)
C)
D)
E)

Question 39

Predict the major product of the reaction sequence shown below.

A)
B)
C)
D)
E)

Question 40

Draw single-barbed arrows to show homolytic bond cleavage in Br₂,shown below.Fill in the products of the reaction.

Question 41

Design a synthetic route to accomplish the transformation shown below,using any reagents necessary.

Question 42

Draw a complete,detailed mechanism for the reaction below,and predict the major product.

Question 43

Draw the propagation steps that occur in the reaction below,and label the type of elementary step for each.

Question 44

Fill in the missing reactants needed to carry out the reaction below.

Question 45

Fill in the starting material and reagents to complete the synthetic scheme below.

Question 46

The chlorine radical abstracts a hydrogen atom from a secondary carbon in preference to a hydrogen atom on a primary carbon in a 4.5:1 ratio.Draw the two possible products that could be obtained from the reaction below,and compute the expected percentage of each product,taking into account the number of each type of hydrogen and the selectivity of chlorine.

Question 47

Devise a synthesis to carry out the following transformation,using any reagents necessary.

Question 48

Predict the major product of the reaction below,and draw a mechanism for the radical addition step.

Question 49

Predict the major product of the reaction below.Draw all possible stereoisomers.

Question 50

Arrange the compounds below in order of increasing rate of halogenation.