Question 1

Which diene and dienophile would you use to prepare the following molecule using a Diels-
Alder cycloaddition reaction:

Accepted Answer

The answer of Which diene and dienophile would you use...

Question 2

Which hydrogen atom(s)of   is/are most susceptible to abstraction by free radicals?

Accepted Answer

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

Question 3

A thermodynamically-controlled reaction will yield predominantly:

Accepted Answer

A)  the more/most stable product. 
B)  the product whose formation requires the smallest free energy of activation. 
C)  the product that can be formed in the fewest steps. 
D)  the product that is formed at the fastest rate. 
E)  the product which possesses the greatest potential energy. 
A)  the more/most stable product. 
B)  the product whose formation requires the smallest free energy of activation. 
C)  the product that can be formed in the fewest steps. 
D)  the product that is formed at the fastest rate. 
E)  the product which possesses the greatest potential energy.

Question 4

Arrange these carbocations in order of expected increasing stability.

Accepted Answer

A)  V < II < I < IV < III 
B)  V<I<II<IV<III 
C)  IV <I< II <V< III 
D)  IV < III < I < II < V 
E)  I < II < IV < III < V 
A)  V < II < I < IV < III 
B)  V<I<II<IV<III 
C)  IV <I< II <V< III 
D)  IV < III < I < II < V 
E)  I < II < IV < III < V

Question 5

What would be the product of the following reaction?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  All of these 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  All of these

Question 6

Which alkene would you expect to have the smallest heat of hydrogenation?

Accepted Answer

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

Question 7

Which carbocation would be most stable?

Accepted Answer

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

Question 8

Which of the following dienes would you expect to be the least stable?

Accepted Answer

A)  CH3CH2CH=CHCH2CH=CHCH3 
B)  CH3CH=CHCH=CHCH2CH3 
C)  CH2=CHCH2CH2CH2CH=CH2 
D)  CH2=CHCH=CHCH2CH2CH3 
E)  CH3CH=C(CH3)CH=CHCH2CH3 
A)  CH3CH2CH=CHCH2CH=CHCH3 
B)  CH3CH=CHCH=CHCH2CH3 
C)  CH2=CHCH2CH2CH2CH=CH2 
D)  CH2=CHCH=CHCH2CH2CH3 
E)  CH3CH=C(CH3)CH=CHCH2CH3

Question 9

Which of the following would afford a synthesis of the following compound?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  None of these 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  None of these

Question 10

What product(s)would you expect from the following substitution reaction of 14C-labeled propene?

Accepted Answer

A)  "14CH2=CH-CH2Cl alone" 
B)  "14CH2=CH-CH2Cl and CH2=CH-14CH2Cl,in equal amounts 
C)  CH2=CH-14CH2Cl alone" 
D)  "more 14CH2=CHCH2Cl,but a little CH2=CH-14CH2Cl" 
E)  "more CH2=CH-14CH2Cl,but a little 14CH2=CHCH2Cl" 
A)  "14CH2=CH-CH2Cl alone" 
B)  "14CH2=CH-CH2Cl and CH2=CH-14CH2Cl,in equal amounts 
C)  CH2=CH-14CH2Cl alone" 
D)  "more 14CH2=CHCH2Cl,but a little CH2=CH-14CH2Cl" 
E)  "more CH2=CH-14CH2Cl,but a little 14CH2=CHCH2Cl"

Question 11

Which pair does not represent a pair of resonance structures?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  All of these represent pairs of resonance structures. 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  All of these represent pairs of resonance structures.

Question 12

Which diene would you expect to react most rapidly with maleic anhydride?

Accepted Answer

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

Question 13

Estimate the stabilization energy for 1,3-cyclohhexadiene using the heats of hydrogenation in Table 1. Table 1.
Heats of Hydrogenation for Selected Compounds
Compound
Moles H2
$\Delta$H(kJ mol-1)
Cyclohexene
1
-120
1,4-Cyclohexadiene
2
-240
1,3-Cyclohexadiene
2
-232
1,5-Hexadiene
2
-253

Accepted Answer

A)  13 kJ mol-1 
B)  21 kJ mol-1 
C)  8 kJ mol-1 
D)  120 kJ mol-1 
E)  112 kJ mol-1 
A)  13 kJ mol-1 
B)  21 kJ mol-1 
C)  8 kJ mol-1 
D)  120 kJ mol-1 
E)  112 kJ mol-1

Question 14

Which of these dienes can undergo the Diels-Alder reaction?

Accepted Answer

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

Question 15

Predict the product of the following Diels-Alder cycloaddition reaction:

Accepted Answer

@#IMG-DLM& Topic Die

Question 16

Draw arrows to indicate the electron flow for the following intramolecular Diels-Alder
cycloaddition reaction:

Accepted Answer

The answer of Draw arrows to indicate the electron flow...

Question 17

Which carbocation would be most stable?

Accepted Answer

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

Question 18

Which of the following dienes is a cumulated diene?

Accepted Answer

A)  CH2=CHCH2CH2CH2CH=CH2 
B)  CH2=CHCH=CHCH2CH2CH3 
C)  CH3CH=C=CHCH2CH2CH3 
D)  CH3CH=CHCH=CHCH2CH3 
E)  CH3CH2CH=CHCH2CH=CH2 
A)  CH2=CHCH2CH2CH2CH=CH2 
B)  CH2=CHCH=CHCH2CH2CH3 
C)  CH3CH=C=CHCH2CH2CH3 
D)  CH3CH=CHCH=CHCH2CH3 
E)  CH3CH2CH=CHCH2CH=CH2

Question 19

Draw the structural formula for (2E,4Z,6E)-3,4,7,8-tetramethyl-2,4,6-nonatriene,clearly indicating stereochemical details.

Accepted Answer

The answer of Draw the structural formula for (2E,4Z,6E)-3,4,7,8-tetramethyl-2,4,6-nonatriene,clearly indicating...

Question 20

What reagents would be needed to synthesize the following substance via the Diels-Alder reaction? Give stereochemical details,as relevant.

Accepted Answer

The answer of What reagents would be needed to synthesize...

Exam 13: Conjugated Unsaturated Systems

Which diene and dienophile would you use to prepare the following molecule using a Diels- Alder cycloaddition reaction:

Which hydrogen atom(s)of is/are most susceptible to abstraction by free radicals?

A thermodynamically-controlled reaction will yield predominantly:

Arrange these carbocations in order of expected increasing stability.

What would be the product of the following reaction?

Which alkene would you expect to have the smallest heat of hydrogenation?

Which carbocation would be most stable?

Which of the following dienes would you expect to be the least stable?

Which of the following would afford a synthesis of the following compound?

What product(s)would you expect from the following substitution reaction of 14C-labeled propene?

Which pair does not represent a pair of resonance structures?

Which diene would you expect to react most rapidly with maleic anhydride?

Estimate the stabilization energy for 1,3-cyclohhexadiene using the heats of hydrogenation in Table 1. Table 1. Heats of Hydrogenation for Selected Compounds Compound Moles H2 Δ\DeltaΔ H(kJ mol-1) Cyclohexene 1 -120 1,4-Cyclohexadiene 2 -240 1,3-Cyclohexadiene 2 -232 1,5-Hexadiene 2 -253

Which of these dienes can undergo the Diels-Alder reaction?

Predict the product of the following Diels-Alder cycloaddition reaction:

Draw arrows to indicate the electron flow for the following intramolecular Diels-Alder cycloaddition reaction:

Which carbocation would be most stable?

Which of the following dienes is a cumulated diene?

Draw the structural formula for (2E,4Z,6E)-3,4,7,8-tetramethyl-2,4,6-nonatriene,clearly indicating stereochemical details.

What reagents would be needed to synthesize the following substance via the Diels-Alder reaction? Give stereochemical details,as relevant.

Carbon Compounds and Chemical Bonds

Representative Carbon Compounds: Functional Groups, Intermolecular Forces, and Infrared Ir Spectroscopy

An Introduction to Organic Reactions: Acids and Bases

Alkanes: Nomenclature, Conformational Analysis, and an Introduction to Synthesis

Stereochemistry: Chiral Molecules

Ionic Reactions - Nucleophilic Substitution and Elimination Reactions of Alkyl Halides

Alkenes and Alkynes I: Properties and Synthesis, Elimination Reactions of Alkyl Halides

Alkenes and Alkynes Ii: Addition Reactions

Nuclear Magnetic Resonance and Mass Spectrometry: Tools for Structure Determination

Radical Reactions

Alcohols and Ethers

Alcohols From Carbonyl Compounds Oxidation-Reduction and Organometallic Compounds

Aromatic Compounds

Reactions of Aromatic Compounds

Aldehydes and Ketones I Nucleophilic Addition to the Carbonyl Group

Aldehydes and Ketones Ii Aldol Reactions

Carboxylic Acids and Their Derivatives Nucleophilic Addition - Elimination at the Acyl Carbon

Synthesis and Reactions of Beta-Dicarbonyl Compounds: More Chemistry of Enolate Ions

Amines

Phenols and Aryl Halides: Nucleophilic Aromatic Substitution

Carbohydrates

Lipids

Amino Acids and Proteins

Nucleic Acids and Protein Synthesis

Filters

What product(s)would you expect from the following substitution reaction of ¹⁴C-labeled propene?

Estimate the stabilization energy for 1,3-cyclohhexadiene using the heats of hydrogenation in Table 1. Table 1. Heats of Hydrogenation for Selected Compounds Compound Moles H₂ $\Delta$ H(kJ mol^-1) Cyclohexene 1 -120 1,4-Cyclohexadiene 2 -240 1,3-Cyclohexadiene 2 -232 1,5-Hexadiene 2 -253