Question 1

If you want to form a kinetic enolate,you want to

Accepted Answer

A) use a strong,non-nucleophilic base such as LDA. 
B) use a protic solvent. 
C) use a low temperature. 
D) both use a strong,non-nucleophilic base such as LDA and use a low temperature. 
A) use a strong,non-nucleophilic base such as LDA. 
B) use a protic solvent. 
C) use a low temperature. 
D) both use a strong,non-nucleophilic base such as LDA and use a low temperature. D

Question 2

It has been found that b-dicarbonyl compounds have a greater concentration of the enol form over the keto form.This can be explained by

Accepted Answer

A) the C=C of the enol is conjugated with the carbonyl group. 
B) the -OH of the enol can hydrogen bond to the oxygen of the nearby carbonyl group. 
C) Both and above are true. 
D) None of the choices are true. 
A) the C=C of the enol is conjugated with the carbonyl group. 
B) the -OH of the enol can hydrogen bond to the oxygen of the nearby carbonyl group. 
C) Both and above are true. 
D) None of the choices are true. C

Question 3

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 B

Question 4

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 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

What is the structure of X,product of the following reaction?

Accepted Answer

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

Question 7

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

Accepted Answer

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

Question 8

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 9

Which is the most acidic proton in the following compound?

Accepted Answer

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

Question 10

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 11

Which of the following is an enol form of the following compound?

Accepted Answer

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

Question 12

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 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

What is the starting material for the following reaction?

Accepted Answer

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

Question 15

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 16

Which is the thermodynamic enolate of 2-methylcyclohexanone?

Accepted Answer

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

Question 17

For most compounds with a single keto group in the molecule,equilibrium favors the keto form over the enol form of the compound.This is due largely to what?

Accepted Answer

A) The C=O bond is much stronger than the C=C bond. 
B) The C=C bond is much stronger than the C=O bond. 
C) The keto form can undergo intramolecular hydrogen bonding. 
D) The enol form can undergo intramolecular hydrogen bonding. 
A) The C=O bond is much stronger than the C=C bond. 
B) The C=C bond is much stronger than the C=O bond. 
C) The keto form can undergo intramolecular hydrogen bonding. 
D) The enol form can undergo intramolecular hydrogen bonding.

Question 18

What is the starting material required to accomplish the following transformation?

Accepted Answer

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

Question 19

Which of the following is a possible enol form of 2-butanone?

Accepted Answer

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

Question 20

If you want to form a thermodynamic enolate,you want to

Accepted Answer

A) keep the reaction as cold as possible. 
B) use an aprotic solvent such as THF. 
C) use a protic solvent such as ethanol. 
D) use a carboxylic acid. 
A) keep the reaction as cold as possible. 
B) use an aprotic solvent such as THF. 
C) use a protic solvent such as ethanol. 
D) use a carboxylic acid.

Exam 21: Substitution Reactions of Carbonyl Compounds at the a Carbon

If you want to form a kinetic enolate,you want to

It has been found that b-dicarbonyl compounds have a greater concentration of the enol form over the keto form.This can be explained by

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

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

What are the three steps in the malonic ester synthesis?

What is the structure of X,product of the following reaction?

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 is the most acidic proton in the following compound?

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

Which of the following is an enol form of the following compound?

Which is the kinetic enolate of 2-methylcyclohexanone?

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

What is the starting material for the following reaction?

Which of the following four compounds is the most acidic?

Which is the thermodynamic enolate of 2-methylcyclohexanone?

For most compounds with a single keto group in the molecule,equilibrium favors the keto form over the enol form of the compound.This is due largely to what?

What is the starting material required to accomplish the following transformation?

Which of the following is a possible enol form of 2-butanone?

If you want to form a thermodynamic enolate,you want to

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 and Addition Reactions

Alkynes and Synthesis

Oxidation and Reduction

Radical Reactions

Conjugation,resonance,and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation and Reduction

Aldehydes and Ketones - Nucleophilic Addition

Carboxylic Acids and the Acidity of the O-H Bond

Carboxylic Acids and Their Derivatives Nucleophilic Acyl Substitution

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond-Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Amino Acids and Proteins

Synthetic Polymers

Lipids

Spectroscopy A: Mass Spectrometry

Spectroscopy B: Infrared Spectroscopy

Spectroscopy C: Nuclear Magnetic Resonance Spectroscopy

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