Deck 23: Nucleophilic Additionelimination Reactions 2: Weak Nucleophiles

Question 1

Which of the following correctly explains how sulfuric acid catalyzes the reaction shown below?

A)The acid increases the rate of nucleophile elimination.
B)The acid increases the nucleophilicity of the alcohol.
C)The acid donates a proton to the alcohol.
D)The acid converts the ester into a carboxylic acid.
E)The acid activates the carbonyl carbon and makes it more electrophilic.

Answer 1

The acid activates the carbonyl carbon and makes it more electrophilic.

Question 2

What is the role of PCl₃ in the following reaction?

A)It converts the carboxylic acid to an enolizable acid chloride.
B)It acts as a base and deprotonates the α carbon.
C)It converts the carboxylic acid to an acid bromide.
D)It activates Br₂ and forms a better nucleophile.
E)It increases the rate of the reaction.

Answer 2

It converts the carboxylic acid to an enolizable acid chloride.

Question 3

Which of the following correctly explains why two equivalents of amine are required for the aminolysis reaction shown below,while alcoholysis requires only one equivalent of alcohol?

A)Amines are less nucleophilic than alcohols.
B)One equivalent of amine acts as a base and is irreversibly protonated.
C)Alcohols are stronger bases than amines.
D)Inductive effects from the Cl make the carbonyl C less electrophilic in aminolysis than in alcoholysis.
E)Two molecules of amine are involved in the rate-determining step.

Answer 3

One equivalent of amine acts as a base and is irreversibly protonated.

Question 4

The reaction below is an example of a(n)_________ reaction,which forms a(n)_________ as a product.

A)hydrolysis, ester
B)aminolysis, amide
C)alcoholysis, ester
D)hydrolysis, carboxylic acid
E)sulfonation, ester

Question 5

Which of the following compounds would undergo hydrolysis at the highest rate?

A)
B)
C)
D)
E)

Question 6

What is the product of the following reaction sequence?

A)
B)
C)
D)
E)

Question 7

What is the major driving force for the reaction below?

A)The product, an acid chloride, is more thermodynamically stable than a carboxylic acid.
B)Chloride is a better nucleophile than hydroxide.
C)The reaction is highly exothermic.
D)Hydroxide is a better leaving group than chloride.
E)The byproducts SO₂ and HCl bubble out of solution irreversibly.

Question 8

Which of the following elementary steps is involved in the mechanism of the reaction shown below?

A)Coordination
B)Proton transfer
C)Bimolecular elimination
D)Electrophilic addition
E)Carbocation rearrangement

Question 9

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

A)
B)
C)
D)
E)

Question 10

How many proton transfer steps occur in the mechanism for the reaction below?

A)0
B)1
C)2
D)3
E)4

Question 11

What base would be the best choice to catalyze the reaction shown below?

A)N(C₂H₅)₃
B)
C)NaOH
D)NaO(CH₂)₃CH₃
E)NaOCH₂CH₃

Question 12

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

A)Proton transfer
B)Electrophilic addition
C)Nucleophilic elimination
D)Bimolecular nucleophilic substitution
E)Nucleophilic addition

Question 13

What is the starting material of the following reaction sequence?

A)
B)
C)
D)
E)

Question 14

Determine the product of the following sequence of reactions.

A)
B)
C)
D)
E)

Question 15

What is the missing reagent needed to complete the synthesis below.

A)
B)
C)H₂O
D)
E)

Question 16

What is the rate-determining step in the mechanism for the following reaction?

A)Bimolecular nucleophilic substitution
B)Coordination
C)Nucleophile elimination
D)Nucleophilic addition
E)Proton transfer

Question 17

Determine the missing starting material for the sequence of reactions shown below.

A)
B)
C)
D)
E)

Question 18

The reaction below is an example of a(n)________ reaction.

A)alcoholysis
B)base-catalyzed transesterification
C)saponification
D)acid-catalyzed transesterification
E)ester hydrolysis

Question 19

Rank the following in order of increasing reaction rate of hydrolysis.

A)2 < 1 < 3
B)1 < 2 < 3
C)1 < 3 < 2
D)3 < 1 < 2
E)2 < 3 < 1

Question 20

Predict the product of the following reaction.

A)
B)
C)
D)
E)

Question 21

What is the major product of the following sequence of reactions?

A)
B)
C)
D)
E)

Question 22

Propose a synthetic route to carry out the following transformation.

Question 23

What is the major product of the following reaction?

A)
B)
C)
D)
E)

Question 24

Which of the following compounds would produce the structure shown below when treated with a base and then acidified?

A)
B)
C)
D)
E)

Question 25

Draw a complete,detailed mechanism for the reaction below,and label the rate-determining step.

Question 26

Determine the product(s)of the following reaction.

Question 27

Predict the major product(s)of the following reaction.

A)
B)
C)
D)
E)

Question 28

Show how the following could be synthesized from hexanoic acid.

Question 29

Indicate which of the following molecules will undergo alcoholysis at a higher rate,and explain why.

Question 30

Draw curved arrows to complete the reaction mechanism shown below,and indicate the rate-determining step.

Question 31

How many dipeptides can be formed in the reaction below?

A)One
B)Two
C)Four
D)Six
E)Eight

Question 32

Draw a complete,detailed mechanism for the reaction below,and predict the product(s).

Question 33

Draw in curved arrows and label the elementary steps in the reaction mechanism below.

Question 34

Draw the mechanism for the following reaction,and label each elementary step.

Question 35

A student attempted to carry out the reaction below,but it was unsuccessful.Explain why the reaction did not work,and suggest a better alternative.

Question 36

Show how you would carry out the following synthesis.

Question 37

Draw a complete,detailed mechanism for the reaction below,label each elementary step,and predict the product.

Question 38

Draw a complete,detailed mechanism for the following reaction,and predict the products.

Question 39

Briefly explain why the following reaction would be unsuccessful.

Question 40

Predict the major product of the following reaction sequence.

A)
B)
C)
D)
E)

Question 41

Identify the N-terminus,the C-terminus,and the peptide bonds in the tripeptide below.

Question 42

The acid-catalyzed transesterification reaction shown below is reversible.What are two specific things you could do to increase the yield of products?

Question 43

Fill in the missing starting material for the reaction below.

Question 44

Suppose that a polypeptide containing 16 amino acid residues is partially hydrolyzed into three smaller peptides,A-C,which are analyzed by Edman degradation and found to have the following sequences.
A: Ala-Ile-Asn
B: Pro-Gln-Cys-Val-Pro-Val
C: Pro-Val-Asp-Ser-Gly-His-Cys-Ala-Ala
What is the original sequence of this polypeptide?

Question 45

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

Question 46

Draw all possible products that could be obtained from the reaction below.

Question 47

Fill in the boxes with an appropriate base and solvent to carry out the reaction below.

Question 48

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

Question 49

Fill in the missing reagents and intermediates to complete the synthesis below.

Question 50

Show how the compound below can be synthesized using a Claisen condensation.Include all necessary reagents.

Question 51

Predict the product of the reaction below,and identify the type of reaction.

Question 52

Show how to carry out the following synthesis using reagents with fewer than five carbon atoms.

Question 53

Show how you would carry out the following transformation,using any necessary reagents.

Question 54

Draw the structures of three additional dipeptides that could be produced in the reaction below,and draw the mechanism for the production of the dipeptide shown.