Deck 16: Ð Bonds With Hidden Leaving Groups

Question 1

What pH range best supports imine formation?

A)0-2
B)2-4
C)4-6
D)6-8

Answer 1

4-6

Question 2

What is the product of the reaction shown below?

A)
B)
C)
D)No reaction would occur.

Answer 2

Question 3

What is the product (or products)of the following reaction?

A)
B)
C)
D)

Answer 3

Question 4

What is the functional group shown below?

A)imine
B)oxime
C)hydrazine
D)hydrazone

Question 5

What is the functional group shown below?

A)imine
B)amine
C)aminal
D)hemiaminal

Question 6

What is the common name for the following heterocycle?

A)furan
B)thiofuran
C)pyridine
D)pyrrole

Question 7

What conditions and reagents will best accomplish the following transformation?

A)1)Propanone,H₃O⁺ 2)NaCNBH₃,3)H₃O⁺
B)2-Bromoproane,Et₃N,DMF
C)2-Propanol,H₃O⁺
D)Ethanoic acid,DCC

Question 8

What is the product of the transformation shown below?

A)
B)
C)
D)

Question 9

Which of the following best describes the carbohydrate shown below?

A)á
B)â
C)D
D)L

Question 10

What reagents and conditions are required for the Wolff-Kischner reduction?

A)1)NH₂NH₂,2)KOH,heat
B)1)MgBrCH₃,2)H₃O⁺
C)MeNH₂,NaCNBH₃,H₃O⁺
D)P₂O₅

Question 11

Figure 1
Referring to Figure 1,how many acetal functional groups are present in the trisaccharide?

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

Question 12

What is the product of the transformation shown below?

A)
B)
C)
D)

Question 13

Figure 1
Referring to Figure 1,from left to right,what is the configuration of each of the three anomeric carbons?

A)â,â,â
B)á,â,á
C)â,á,â
D)á á á

Question 14

Which conditions are required for the following transformation?

A)HCl,H₂O
B)KOH,heat
C)NaCNBH₃
D)Pd,H₂

Question 15

What is the functional group shown below?

A)imine
B)amine
C)enamine
D)oxime

Question 16

Figure 1
Referring to Figure 1,how many hemiacetal functional groups are present in the trisaccharide?

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

Question 17

Which of the following products will result from the heterocyclic condensation reaction shown below?

A)
B)
C)
D)

Question 18

What is the functional group shown below?

A)ether
B)acetal
C)hemiacetal
D)oxonium

Question 19

What is the role of P₂O₅ in the reaction shown below?

A)to activate the carbonyl as an electrophile
B)to deprotonate the ketone
C)to bring the oxygens together for cyclization
D)to absorb the resultant water formed in the reaction

Question 20

What is the intermediate of the transformation shown below?

A)
B)
C)
D)The reaction is concerted and no intermediate is formed.

Question 21

Which of the following imines will NOT form an imine with a ketone?

A)
B)
C)
D)

Question 22

What is the major product of the reaction scheme shown below?

A)
B)
C)
D)No reaction would occur.

Question 23

What is the role of sulfuric acid in the following reaction?

A)nucleophile
B)catalyst
C)solvent
D)dehydrating agent

Question 24

Which of the following is NOT a possible reaction scheme to obtain the final product shown below?

A)1)NH₃ 2)HNO₃/H₂SO₄
B)NH₂OH,H₃O⁺
C)1)NH₃ 2)P₂O₅
D)1)NH₃ 2)DDQ

Question 25

Which of the following structures represents a hemiaminal?

A)
B)
C)
D)

Question 26

Which of the following amines will most readily form an enamine with a ketone?

A)
B)
C)
D)

Question 27

An amine and a ketone can condense to form an imine.

Question 28

What is the major product of the reaction scheme shown below?

A)
B)
C)
D)

Question 29

What is the major product of the reaction scheme shown below?

A)
B)
C)
D)

Question 30

Which conditions would push the forward direction (I)and the reverse direction (II)in the following reaction scheme?

A)(I)- H⁺ (II)- H⁺
B)(I)- H⁺ (II)- H⁺ /H₂O
C)(I)- H⁺ /H₂O (II)- H⁺
D)(I)- H⁺ /H₂O II)- H⁺ /H₂O

Question 31

What reagents would accomplish the following transformation?

A)KOH,heat
B)AcOH,H₂O
C)NaCNBH₃,AcOH,H₂O
D)DDQ,H₂O

Question 32

What would be the major product of the following reaction?

A)
B)
C)
D)No reaction would occur.

Question 33

The products of acetal formation from a ketone are shown below.Which reactant did the oxygen in water come from?

A)acetone
B)methanol
C)50% acetone,50% methanol
D)TsOH

Question 34

What is the major product of the reaction shown below?

A)
B)
C)
D)

Question 35

What would be the product of the following reaction?

A)
B)
C)
D)No reaction would occur.

Question 36

Which reagents are required to achieve the following transformation?

A)HCl_(trace), H₂O
B)HCl_(trace), MeOH
C)HCl_(trace), H₂O,MeOH
D)HCl_(trace),

Question 37

Acetal formation is reversible.

Question 38

When the hydroxyl group of a cyclic carbohydrate at the anomeric position is axial,it is designated á.

Question 39

Hydrazine and ketone can condense to form a semicarbazone.

Question 40

What would be the major product of the following reaction?

A)
B)
C)
D)No reaction would occur.

Question 41

The anomeric carbon is the penultimate carbon of a linear carbohydrate.

Question 42

Water is the hidden leaving group of carbonyls.

Question 43

The carbonyl oxygen in a ketone/aldehyde is retained when transformed into an acetal.

Question 44

The first mechanistic step in forming an acetal from an aldehyde is nucleophilic attack on the carbonyl by an alcohol.

Question 45

DHF is used as a protecting group for aldehydes and ketones.

Question 46

Anomers are the result of the formation of an sp³ carbon through the hemiacetal formation of cyclic sugars.

Question 47

Cyclic acetals form faster than open chain acetals.

Question 48

A pyrrole is a sulfur containing heterocycle.

Question 49

A Dean-Stark trap is used to drive the acetal formation reaction forward.

Question 50

Pyridine can be produced from hydroxylamine and a 1,5-dione

Question 51

Cyclic hemiacetals are more common than open-chain acetals.

Question 52

Acetals can protect aldehydes and ketones from Grignard reactions.

Question 53

1,2 diols form acetals faster than alcohols with ketones and aldehydes.

Question 54

P₂O₅ is used in the production of furans.

Question 55

Enamines are most readily formed with secondary amines.

Question 56

Aldehydes form acetals faster than ketones.

Question 57

Acetal formation is both acid and base catalyzed.

Question 58

The D and L designations of carbohydrates represent the orientation of the penultimate carbon in the fisher projection.

Question 59

A quantitative amount of acid is required to convert an acetal back to an aldehyde and diol.

Question 60

Dihydropyran is used as a protecting group for aldehydes.

Question 61

_______________ is the common name for an aromatic five-membered ring structure containing an endocyclic nitrogen atom.

Question 62

A â sugar is one where the anomeric hydroxyl group and the furthest ring substituent are _______________ to each other.

Question 63

Propose a mechanism for the reaction shown below.

Question 64

Draw a mechanism for the following reaction.

Question 65

Hydroxylamine and ketones condense with each other to form a(n)_______________ .

Question 66

Identify all the products formed when the compound below is treated with aqueous acid.

Question 67

A change to a functional group to reduce its chemical reactivity is referred to as a(n)_______________ .

Question 68

A D sugar is one where the hydroxyl group on the _______________ carbon points to the right in the Ficsher projection.

Question 69

Cyclization of a carbohydrate leads to the formation of an acetal.

Question 70

Propose a mechanism for the transformation shown below.

Question 71

The reaction of an aldehyde and an amine forms a(n)_______________ .

Question 72

The condensation of an amine with a ketone or aldehyde to form an imine occurs fastest around pH 5.The rate of reaction slows as the pH increases and decreases.Explain this observation.

Question 73

Propose a mechanism for the following transformation.

Question 74

Show the mechanism of the following reaction.

Question 75

An aromatic 5-membered ring containing an oxygen atom is known as a(n)_______________ .

Question 76

Suggest a sequence of reactions that would accomplish the following transformation.Show all intermediate molecules made.

Question 77

Propose a synthetic scheme to obtain the following product.Show all intermediate structures.

Question 78

_______________ is required to make furan from a di-one.

Question 79

The condensation of hydrazine with a ketone forms a(n)_______________ .

Question 80

DDQ is used as a(n)_______________ in the formation of pyridine derivatives.