Deck 15: Substitution Reactions of Aromatic Compounds

Question 1

Why is one equivalent of AlCl₃ required for the transformation shown here?

A) Either the oxygen or the chlorine in the acyl chloride can attach to the Al atom in AlCl₃.
B) AlCl₃ is needed to produce the acyl chloride during the course of the reaction.
C) The product forms a complex with the AlCl₃.
D) The product would rearrange unless there were extra. AlCl₃ present.
E) Both benzene and the acyl chloride form complexes with the AlCl₃.

Answer 1

The product forms a complex with the AlCl₃.

Question 2

Which reagent would you use to accomplish the transformation shown?

A) Br₂
B) Br₂/FeBr₃
C)CuBr
D)Br₂/AlBr₃
E) HBr

Answer 2

CuBr

Question 3

Which conditions would you use to accomplish the following transformation?

A) HNO₃/H₂SO₄
B)KOH, H₂NNH₂, ethylene glycol
C)HNO₃/ H₂SO₄, then H₂/Pd/C
D)HNO₃/H₂SO₄, then H₂O
E) Na, NH₃

Answer 3

HNO₃/ H₂SO₄, then H₂/Pd/C

Question 4

What is the electrophile in this reaction?

A) HNO₃
B) H₂SO₄
C) SO₃
D) NO₂⁺
E) Benzene

Question 5

Which of the following statements is false?

A)Hydrogenation of benzene is possible.
B)Hydrogenation of benzene is endothermic.
C)Hydrogenation of benzene requires special conditions, such as increased heat or pressure or special catalysts.
D)Hydrogenation of benzene requires 3 moles of hydrogen gas.
E)The transformation of benzene to cyclohexane has a high activation energy.

Question 6

What is the proper description of the compound shown here?

A) diazonium salt
B) nitroso compound
C) aniline
D) anilinium ion
E) diazotic acid

Question 7

What is the electrophile in this reaction?

A) Br₂
B) FeBr₃
C) FeBr₄^-
D) Benzene
E)FeBr₅⁺

Question 8

Which of the following compounds is activated in electrophilic aromatic substitution reaction relative to benzene?

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

Question 9

Which of the following would not react with the compound shown?

A) KI
B) CuCN
C) CuBr
D) HCl
E) HBF₄

Question 10

What is the electrophile in this reaction?

A) H₂SO₄
B) SO₃
C) HSO₃⁺
D) Benzene
E) HSO₄^-

Question 11

Which of the following statements is true?

A)All meta directors are electron-withdrawing groups.
B)All electron-withdrawing groups are meta directors.
C)All ortho, para directors are activating.
D)All ortho, para directors are deactivating.
E)All electron-donating groups are meta directors.

Question 12

Which of the following substrates would not provide a rearranged product when reacted with benzene in a Friedel-Crafts alkylation reaction?

A)
B)
C)
D)
E)

Question 13

What is the electrophile in the reaction shown here?

A)
B) AlCl₃
C)
D)
E) Benzene

Question 14

Which of the following statements is false?

A)Halogenated benzenes have higher boiling points than benzene.
B)Halogen atoms donate electron density to the ring by resonance.
C)Halogen atoms are deactivating in electrophilic aromatic substitution.
D)Halogen atoms are meta directors.
E)Halogen atoms withdraw electron density from the ring inductively.

Question 15

Which of these compounds is the product of the reaction shown?

A)

B)

C)

D)

E)

Question 16

What is the product of the following reaction?

A)

B)

C)

D)

E)
No reaction occurs.

Question 17

What is the missing reagent in the following reaction sequence?

A) CO, HCl
B) H₃O⁺
C) NaNO₂ , then H₃PO₂
D) H₃PO₂
E) Na, NH₃

Question 18

Which of the following compounds is deactivated in electrophilic aromatic substitution reaction relative to benzene?

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

Question 19

What is the major product of nitration of thiophene?

A)

B)

C)

D)

E) No reaction occurs.

Question 20

Which reagent set could not be used to accomplish the transformation shown here?

A) H₂/ Pd / C, EtOH
B) Sn/HCl , then OH-(aq)
C) LiAlH₄, then H₂O
D) KMnO₄
E) any of these reagents could be used

Question 21

Which of the following statements about benzyne is false?

A) The geometry around the alkyne is bent.
B) There are four hydrogen atoms.
C) Each of the two π because bonds in the alkyne results from overlap of 2p orbitals on adjacent carbons.
D) One of the π bonds is involved in the ring's π system, while the other is not.
E) The compound is strained and highly reactive.

Question 22

Which of these is the product of the reaction shown here?

A)

B)

C)

D)

E) No reaction occurs.

Question 23

Predict the major organic product and draw the structure of the electrophile in the following
reaction.

Question 24

Explain why benzene is inert to treatment with hydrogen gas unless special conditions are used.

Question 25

Which of the following statements about the reaction shown here is true?

A) The ortho and para pathways are disfavored because of steric hindrance.
B) Sulfuric acid and nitric acid in combination direct groups to the meta position on the ring.
C) The intermediate for the ortho and para pathways has positive and partial positive charges on adjacent atoms whereas the meta pathway intermediate does not.
D) Reaction produces benzoic action.
E) The reaction is a Friedel-Crafts acylation.

Question 26

Draw the structure of the electrophile in the reaction shown.

Question 27

Draw an energy diagram for the chlorination of benzene.Include all intermediates and show their
relative energies.

Question 28

Bromination of aniline results in 2,4,6 -tribromoaniline. Which of the following compounds will be mono-brominated in para position upon treatment with and a Lewis acid catalyst?

A)

B)

C)

D)

E)

Question 29

Which of the following compounds will undergo nucleophilic aromatic substitution with methoxide ion at the fastest rate?

A)

B)1
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C)

D)

E)

Question 30

Which of the following compounds is the major product of this reaction?

A)

B)

C)

D)

E)

Question 31

Shown below is an electrophilic aromatic substitution reaction. Which of the following statements about this reaction is/are true?

I. The products of ortho and para substitution are favored in the overall reaction.
II. The product of meta substitution is favored in the overall reaction.
III. For all three substitution pathways (ortho, meta, and para) the transition state in the rate-limiting step is lower in energy than the transition state for rate-limiting step in the bromination of benzene.
IV. Compared to the energy of the transition state for the rate-limiting step in the bromination of benzene, the transition state in the rate-limiting step for this reaction is lower in energy for the ortho and para pathways, but higher in energy for the meta pathway.

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

Question 32

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

Question 33

Predict the product of the following reaction.

Question 34

Which of the following compounds is the major product of this reaction?

A)
B)
C)
D)
E)

Question 35

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

Question 36

Predict the product of the following reaction.

Question 37

Which of the following compounds do you expect to most readily undergo Diels-Alder reaction with a dienophile?

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

Question 38

Draw the energy diagram for the following reaction.

Question 39

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

Question 40

What is the major product of the reaction shown here?

A)
B)
C)
D) Both a and c will form.
E) None of these products can form under these conditions.

Question 41

What conditions are required to synthesize the molecule shown from benzene?

Question 42

What is the product of the following reaction?

Question 43

Aniline is more activating towards electrophilic aromatic substitution than phenol.Explain.

Question 44

Design a multistep synthesis for the following transformation.You may use any organic or inorganic reagents.Show the reagents needed for each step and the product of each step.

Question 45

A chemist attempted the following Friedel-Crafts alkylation and did not successfully isolate the intended product: Explain what product the chemist most likely did isolate and why, and provide an alternate pathway starting from benzene that would provide the intended product.

Question 46

Phenol usually reacts easily with electrophiles.However, nitration of phenol with nitric acid is unsuccessful since the oxidation of phenol to p-quinone is faster than the electrophilic substitution. However, the nitration reaction shown below is successful. Explain why the reactivity of starting material is different from that of phenol. Draw the nitration product.

Question 47

Predict the product of the following reaction and show the product after the first step.

Question 48

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

Question 49

Design a multistep synthesis for the transformation shown using a Friedel-Crafts acylation as one of the steps.You may use any organic or inorganic reagents.Show the reagents needed for each step and the product of each step.

Question 50

Predict the major organic product and draw the structure of the electrophile in the reaction shown here.

Question 51

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

Question 52

Draw the structure of the electrophile in the following reaction.

Question 53

Predict the major product of the following reaction.

Question 54

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

Question 55

Benzene is subjected to an electrophilic aromatic substitution reaction, yielding a single product. This product is then subjected to the same reaction again.The reaction is successful, though slower than the first, and two products result.One of these, product A, has two signals in the aromatic region of the 1H NMR spectrum, while the other, product B, has only one signal.Propose possible structures for A and B.

Question 56

Predict the product of the following reaction.

Question 57

Provide the missing reagents in this scheme.

Question 58

Design a multistep synthesis for the following transformation.You may use any organic or inorganic reagents.Show the reagents needed for each step and the product of each step.

Question 59

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

Question 60

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

Question 61

Explain why furan undergoes the Diels-Alder reaction, but benzene typically does not.

Question 62

The following reaction yields two products.Draw their structures.

Question 63

Design a multistep synthesis to produce o-bromoaniline as the sole product using aniline as the
starting material (i.e., you must avoid generating over-brominated products and p-bromoaniline).
You may use any organic or inorganic reagents.Show the reagents needed for each step and the
product of each step.

Question 64

Predict the product of the following reaction.

Question 65

What is the product of the following reaction?

Question 66

Design a multistep synthesis for the following transformation.You may use any organic or
inorganic reagents.Show the reagents needed for each step and the product of each step.

Question 67

What is the product of the following reaction?

Question 68

Design a synthesis of the target molecule shown from benzene and any organic or inorganic
reagents.Show the reagents needed for each step and the product of each step.