Deck 20: Enols and Enolates

Question 1

Which one of the following cannot form an enolate anion?

A) 2,2-dimethylbutanal
B) 2,3-dimethylbutanal
C) 2-ethylbutanal
D) 3,3-dimethylbutanal

Answer 1

2,2-dimethylbutanal

Question 2

Which one of the following has two different enol forms?

A) cyclohexanone
B) 3,3-dimethylcyclohexanone
C) 2,2-dimethylcyclohexanone
D) 4,4-dimethylcyclohexanone

Answer 2

3,3-dimethylcyclohexanone

Question 3

Identify the most acidic hydrogen in the following compound.

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

Answer 3

2

Question 4

What is the product of the reaction below?

A)

B)

C)

D)

Question 5

Which one of the following optically active compounds racemizes in dilute $\mathrm{KOH} / \mathrm{CH}_{3} \mathrm{OH}$ solution?

A)

B)

C)

D)

Question 6

What is the aldol addition product of propanal?

A) 2-hydroxy-2-methylpentanal
B) 3-hydroxy-2-methylpentanal
C) 3-hydroxyhexanal
D) 4-hydroxyhexanal

Question 7

Identify the starting reagent needed to make the following cyclic ketone by an intramolecular aldol condensation reaction.

A)

B)

C)

D)

Question 8

The Robinson annulation reaction is shown below. Identify the missing reagent in the first step.

A)

B)

C)

D)

Question 9

Which of the following is the Claisen condensation product of ethyl propanoate, $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CO}_{2} \mathrm{Et}$ ?

A)
B)
C)
D)

Question 10

Identify the missing reagent in the reaction shown below.

A) ethyl formate, $\mathrm{HCO}_{2} \mathrm{Et}$
B) diethyl carbonate, $(\mathrm{EtO})_{2} \mathrm{C}=\mathrm{O}$
C) diethyl oxalate, $\mathrm{EtO}_{2} \mathrm{CCO}_{2} \mathrm{Et}$
D) ethyl acetate, $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{Et}$

Question 11

What is the missing reagent in the synthesis shown below?

A) bromocyclopentane
B) 1,4-dibromobutane
C) 1,5-dibromopentane
D) 1,1-dibromocyclopentane

Question 12

Which of the following is the Michael addition product of the reaction below?

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

Question 13

What would result from treating (-)-menthone with basic $\mathrm{D}_{2} \mathrm{O}$ ?

A)

B)

C)

D) more than one of these is formed

Question 14

The compound shown below undergoes a retro (reverse) aldol reaction under these conditions. What product(s) result(s)?

A)

B)

C)

D)