Question 1

Which diene and dienophile would you choose to synthesize the following compound?

Accepted Answer

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

Question 2

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

Accepted Answer

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

Question 3

Which of the following compounds would be the most stable?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  They are all of equal stability. 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  They are all of equal stability.

Question 4

Which is the major product of the following reaction?

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 5

The alkaloid colchicine is used in the treatment of gout.The first synthetic colchine
involved the preparation of the key intermediate shown.Which combination of diene and
dieneophile will result in its preparation?

Accepted Answer

The answer of The alkaloid colchicine is used in the...

Question 6

Draw arrows to indicate electron movement that explains the formation of the products
shown for the following retro-Diels-Alder reaction:

Accepted Answer

The answer of Draw arrows to indicate electron movement that...

Question 7

When the product distribution for a particular reaction reflects the relative stabilities of the products,the reaction is said to be under ______________ control.

Accepted Answer

The answer of When the product distribution for a particular...

Question 8

Considering both configurational and conformational factors,select the least stable form of 2,4-hexadiene.

Accepted Answer

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

Question 9

Which hydrogen atom(s)of   is/are least 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 10

Polyenes in which single and double bonds alternate along the carbon chain are called ___________.

Accepted Answer

The answer of Polyenes in which single and double bonds...

Question 11

Which of the following compounds is not formed as a result of a chain-termination step in the free radical chlorination of propene?

Accepted Answer

A)  CH2=CHCH2Cl 
B)  Cl2 
C)  CH2=CHCH2CH2CH=CH2 
D)  HCl 
E)  All can be formed in chain-termination steps. 
A)  CH2=CHCH2Cl 
B)  Cl2 
C)  CH2=CHCH2CH2CH=CH2 
D)  HCl 
E)  All can be formed in chain-termination steps.

Question 12

The allyl cation has how many bonding  $\pi$molecular orbitals?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 13

Which free radical would be least stable?

Accepted Answer

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

Question 14

The allyl cation has how many  $\pi$ molecular orbitals?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 15

Select the structure of the isolated diene.

Accepted Answer

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

Question 16

Arrange these hexadienes in order of expected decreasing stability.

Accepted Answer

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

Question 17

What is an IUPAC name for this triene?

Accepted Answer

A)  (2E,4Z,6
E) -2,4,6-Nonatriene 
B)  (2Z,4E,6Z)-2,4,6-Nonatriene 
C)  (2E,4Z,6Z)-2,4,6-Nonatriene 
D)  (3Z,5Z,7
E) -3,5,7-Nonatriene 
E)  (3Z,5E,7
E) -3,5,7-Nonatriene 
A)  (2E,4Z,6
E) -2,4,6-Nonatriene 
B)  (2Z,4E,6Z)-2,4,6-Nonatriene 
C)  (2E,4Z,6Z)-2,4,6-Nonatriene 
D)  (3Z,5Z,7
E) -3,5,7-Nonatriene 
E)  (3Z,5E,7
E) -3,5,7-Nonatriene

Question 18

The allyl radical has how many electrons in non-bonding  $\pi$ molecular orbitals?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 19

Which reagent would convert 1,3-pentadiene into 3-penten-2-ol?

Accepted Answer

A)  KMnO4/-OH 
B)  OsO4 
C)  H2O2,then H3O+ 
D)  Cl2/H2O 
E)  H3O+ 
A)  KMnO4/-OH 
B)  OsO4 
C)  H2O2,then H3O+ 
D)  Cl2/H2O 
E)  H3O+

Question 20

Estimate the stabilization energy for 1,3-pentadiene using the heats of hydrogenation in Table 1. Table 1.
Heats of Hydrogenation for Selected Compounds
Compound
Moles H2
$\Delta$H(kJ mol-1)
1-Butene
1
-127
1-Pentene
Trans-2-pentene
1
1
-126
-115
1,3-Butadiene
2
-239
Trans-1,3-Pentadiene
2
-226

Accepted Answer

A)  13 kJ mol-1 
B)  15 kJ mol-1 
C)  28 kJ mol-1 
D)  239 kJ mol-1 
E)  112 kJ mol-1 
A)  13 kJ mol-1 
B)  15 kJ mol-1 
C)  28 kJ mol-1 
D)  239 kJ mol-1 
E)  112 kJ mol-1

Exam 13: Conjugated Unsaturated Systems

Which diene and dienophile would you choose to synthesize the following compound?

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

Which of the following compounds would be the most stable?

Which is the major product of the following reaction?

The alkaloid colchicine is used in the treatment of gout.The first synthetic colchine involved the preparation of the key intermediate shown.Which combination of diene and dieneophile will result in its preparation?

Draw arrows to indicate electron movement that explains the formation of the products shown for the following retro-Diels-Alder reaction:

When the product distribution for a particular reaction reflects the relative stabilities of the products,the reaction is said to be under ______________ control.

Considering both configurational and conformational factors,select the least stable form of 2,4-hexadiene.

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

Polyenes in which single and double bonds alternate along the carbon chain are called ___________.

Which of the following compounds is not formed as a result of a chain-termination step in the free radical chlorination of propene?

The allyl cation has how many bonding π\piπ molecular orbitals?

Which free radical would be least stable?

The allyl cation has how many π\piπ molecular orbitals?

Select the structure of the isolated diene.

Arrange these hexadienes in order of expected decreasing stability.

What is an IUPAC name for this triene?

The allyl radical has how many electrons in non-bonding π\piπ molecular orbitals?

Which reagent would convert 1,3-pentadiene into 3-penten-2-ol?

Estimate the stabilization energy for 1,3-pentadiene 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) 1-Butene 1 -127 1-Pentene Trans-2-pentene 1 1 -126 -115 1,3-Butadiene 2 -239 Trans-1,3-Pentadiene 2 -226

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

The allyl cation has how many bonding $\pi$ molecular orbitals?

The allyl cation has how many $\pi$ molecular orbitals?

The allyl radical has how many electrons in non-bonding $\pi$ molecular orbitals?

Estimate the stabilization energy for 1,3-pentadiene using the heats of hydrogenation in Table 1. Table 1. Heats of Hydrogenation for Selected Compounds Compound Moles H₂ $\Delta$ H(kJ mol^-1) 1-Butene 1 -127 1-Pentene Trans-2-pentene 1 1 -126 -115 1,3-Butadiene 2 -239 Trans-1,3-Pentadiene 2 -226