Question 1

Why is the enolate of acetone less basic than the allyl anion derived from propene?

Accepted Answer

A) Because there are more atoms in acetone 
B) Because there are more resonance structures for the enolate of acetone 
C) It isn't; the allyl anion is less basic. 
D) One of the resonance structures for the enolate places the negative charge on the more electronegative oxygen. 
A) Because there are more atoms in acetone 
B) Because there are more resonance structures for the enolate of acetone 
C) It isn't; the allyl anion is less basic. 
D) One of the resonance structures for the enolate places the negative charge on the more electronegative oxygen.

Question 2

Why is it difficult to stop the halogenation of ketones under basic conditions at the mono-halogenated stage?

Accepted Answer

A) The ketone undergoes a Bayer-Villigar oxidation. 
B) The ketone is reduced. 
C) The ketone undergoes an Aldol reaction. 
D) The bromine helps to stabilize the second enolate, making the product more acidic than the starting material. 
A) The ketone undergoes a Bayer-Villigar oxidation. 
B) The ketone is reduced. 
C) The ketone undergoes an Aldol reaction. 
D) The bromine helps to stabilize the second enolate, making the product more acidic than the starting material.

Question 3

Vitamin C is a stable enediol.Which is the structure of a possible keto form in equilibrium with the enediol form?

Accepted Answer

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

Question 4

Starting with cyclohexanone, how could you prepare the diketone below?

Accepted Answer

A) Treat cyclohexanone with a base under thermodynamic conditions. 
B) Hydrogenate cyclohexanone with Raney nickel. 
C) Convert cyclohexanone into the a-bromoketone and then react this with the enolate of cyclohexanone. 
D) Convert cyclohexanone into an enamine with diethylamine and then react this with more cyclohexanone. 
A) Treat cyclohexanone with a base under thermodynamic conditions. 
B) Hydrogenate cyclohexanone with Raney nickel. 
C) Convert cyclohexanone into the a-bromoketone and then react this with the enolate of cyclohexanone. 
D) Convert cyclohexanone into an enamine with diethylamine and then react this with more cyclohexanone.

Question 5

What are the three steps in the malonic ester synthesis?

Accepted Answer

A) Deprotonation, alkylation, hydrolysis/decarboxylation 
B) Hydrogenation, alkylation, deprotonation 
C) Alkylation, hydrolysis/decarboxylation.hydrogenation 
D) Hydrolysis/decarboxylation, deprotonation, alkylation 
A) Deprotonation, alkylation, hydrolysis/decarboxylation 
B) Hydrogenation, alkylation, deprotonation 
C) Alkylation, hydrolysis/decarboxylation.hydrogenation 
D) Hydrolysis/decarboxylation, deprotonation, alkylation

Question 6

Will acetophenone be completely deprotonated by lithium diisopropylamide (LDA)?

Accepted Answer

A) Yes 
B) No 
A) Yes 
B) No

Question 7

The reaction below is a direct enolate alkylation.It has been found that this reaction only works well with unhindered methyl and 1° alkyl halides.Pick the statement that best explains this observation.

Accepted Answer

A) The nucleophilic enolate requires a reaction center that has a positive charge. 
B) Hindered alkyl halides do not undergo SN1 reactions. 
C) Hindered alkyl halides do not undergo SN2 reactions. 
D) Methyl and 1° alkyl halides can form carbocations that can readily react with the nucleophilic enolate. 
A) The nucleophilic enolate requires a reaction center that has a positive charge. 
B) Hindered alkyl halides do not undergo SN1 reactions. 
C) Hindered alkyl halides do not undergo SN2 reactions. 
D) Methyl and 1° alkyl halides can form carbocations that can readily react with the nucleophilic enolate.

Question 8

Which of the following four compounds is the most acidic?

Accepted Answer

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

Question 9

The malonic ester synthesis can be adapted to synthesize a-amino acids by using diethyl acetamidomalonate as the starting material.Select the structure of the amino acid produced by the following synthesis.

Accepted Answer

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

Question 10

Will acetone be completely deprotonated by potassium tert-butoxide?

Accepted Answer

A) Yes 
B) No 
A) Yes 
B) No

Question 11

What is the starting material in the following reaction?

Accepted Answer

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

Question 12

The following molecule is called:

Accepted Answer

A) a 1,3-diketopentanoate. 
B) a diethyl malonate. 
C) an ethyl acetoacetate. 
D) a b-keto ester. 
A) a 1,3-diketopentanoate. 
B) a diethyl malonate. 
C) an ethyl acetoacetate. 
D) a b-keto ester.

Question 13

Which of the following are enol forms of ethyl acetoacetate drawn below?

Accepted Answer

A) Only I 
B) Only II 
C) Only III 
D) I, II, and III 
A) Only I 
B) Only II 
C) Only III 
D) I, II, and III

Question 14

Which of the following compounds is an enol of compound X drawn below?

Accepted Answer

A) Only I 
B) Only II 
C) Only III 
D) Only I and II 
A) Only I 
B) Only II 
C) Only III 
D) Only I and II

Question 15

What is the major product of the following reaction?

Accepted Answer

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

Question 16

Which is the kinetic enolate of 2-methylcyclohexanone?

Accepted Answer

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

Question 17

Select the appropriate sequence of reactions to accomplish the following synthesis.

Accepted Answer

A) [1] Br2, CH3CO2H; [2] Li2CO3, LiBr, DMF; [3] CH3CH2CH2CH2Br 
B) [1] Br2, CH3CO2H; [2] Mg, Et2O; [3] CH3CH2CH2CH2Br 
C) [1] LDA; [2] BrCH2CH2CH2CH2Br; [3] NaOEt 
D) [1] NaOEt; [2] BrCH2CH2CH2CH2Br; [3] LDA 
A) [1] Br2, CH3CO2H; [2] Li2CO3, LiBr, DMF; [3] CH3CH2CH2CH2Br 
B) [1] Br2, CH3CO2H; [2] Mg, Et2O; [3] CH3CH2CH2CH2Br 
C) [1] LDA; [2] BrCH2CH2CH2CH2Br; [3] NaOEt 
D) [1] NaOEt; [2] BrCH2CH2CH2CH2Br; [3] LDA

Question 18

Which of the following ketones will give a positive iodoform test?

Accepted Answer

A) 3-Heptanone 
B) 2-Pentanone 
C) 3-Hexanone 
D) Cyclohexanone 
A) 3-Heptanone 
B) 2-Pentanone 
C) 3-Hexanone 
D) Cyclohexanone

Question 19

What is the product of the following reaction?

Accepted Answer

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

Question 20

Which of the following compounds is the most acidic?

Accepted Answer

A) Ethyl acetoacetate 
B) 2-Butanone 
C) 1-Butanol 
D) 3-Pentanone 
A) Ethyl acetoacetate 
B) 2-Butanone 
C) 1-Butanol 
D) 3-Pentanone

Exam 23: Substitution Reactions of Carbonyl Compounds at the Alpha-Carbon

Why is the enolate of acetone less basic than the allyl anion derived from propene?

Why is it difficult to stop the halogenation of ketones under basic conditions at the mono-halogenated stage?

Vitamin C is a stable enediol.Which is the structure of a possible keto form in equilibrium with the enediol form?

Starting with cyclohexanone, how could you prepare the diketone below?

What are the three steps in the malonic ester synthesis?

Will acetophenone be completely deprotonated by lithium diisopropylamide (LDA)?

The reaction below is a direct enolate alkylation.It has been found that this reaction only works well with unhindered methyl and 1° alkyl halides.Pick the statement that best explains this observation.

Which of the following four compounds is the most acidic?

The malonic ester synthesis can be adapted to synthesize a-amino acids by using diethyl acetamidomalonate as the starting material.Select the structure of the amino acid produced by the following synthesis.

Will acetone be completely deprotonated by potassium tert-butoxide?

What is the starting material in the following reaction?

The following molecule is called:

Which of the following are enol forms of ethyl acetoacetate drawn below?

Which of the following compounds is an enol of compound X drawn below?

What is the major product of the following reaction?

Which is the kinetic enolate of 2-methylcyclohexanone?

Select the appropriate sequence of reactions to accomplish the following synthesis.

Which of the following ketones will give a positive iodoform test?

What is the product of the following reaction?

Which of the following compounds is the most acidic?

Structure and Bonding

Acids and Bases

Introduction to Organic Molecules and Functional Groups

Alkanes

Stereochemistry

Understanding Organic Reactions

Alkyl Halides and Nucleophilic Substitution

Alkyl Halides and Elimination Reactions

Alcohols, Ethers, and Related Compounds

Alkenes

Alkynes

Oxidation and Reduction

Mass Spectrometry and Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Radical Reactions

Conjugation, Resonance, and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Carboxylic Acids and the Acidity of the O-H Bond

Introduction to Carbonyl Chemistry;

Aldehydes and Ketones Nucleophilic Addition

Carboxylic Acids and Derivatives

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Amino Acids and Proteins

Synthetic Polymers

Lipids

Filters