Question 1

The LUMO of 1,3-pentadiene has how many electrons in its ground state?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  0 
A)  1 
B)  2 
C)  3 
D)  4 
E)  0

Question 2

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 3

UV-vis spectroscopy can be used to indicate whether _________________ is present.

Accepted Answer

The answer of UV-vis spectroscopy can be used to indicate...

Question 4

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

Accepted Answer

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

Question 5

Treatment of 2-butene (cis or trans)with Cl2 at 400  $\degree$C would yield mainly:

Accepted Answer

A)  CH2ClCHClCH2CH3 
B)  CH3CHClCH2CH3 
C)  CH3CH=CClCH3  
D)  CH3CH=CHCH2Cl and  CH3CHClCH=CH2  
E)  CH3CHClCHClCH3 
A)  CH2ClCHClCH2CH3 
B)  CH3CHClCH2CH3 
C)  CH3CH=CClCH3  
D)  CH3CH=CHCH2Cl and  CH3CHClCH=CH2  
E)  CH3CHClCHClCH3

Question 6

How could the following synthesis be carried out?

Accepted Answer

A)  (1)Br2/CCl4; (2)CH3CH2MgCl,ether; (3)CH3ONa/CH3OH 
B)  (1)HBr,80$\degree$C; (2)(CH3CH2)2CuLi,ether 
C)  (1)HBr,80$\degree$C; (2)Mg,ether; (3)CH3CH2OH,then H3O+ 
D)  More than one of the above 
E)  All of the above 
A)  (1)Br2/CCl4; (2)CH3CH2MgCl,ether; (3)CH3ONa/CH3OH 
B)  (1)HBr,80$\degree$C; (2)(CH3CH2)2CuLi,ether 
C)  (1)HBr,80$\degree$C; (2)Mg,ether; (3)CH3CH2OH,then H3O+ 
D)  More than one of the above 
E)  All of the above

Question 7

A reaction under kinetic (or rate)control will yield predominantly:

Accepted Answer

A)  the most stable product. 
B)  the product that can be formed in the fewest steps. 
C)  the product whose formation requires the smallest free energy of activation. 
D)  the product with the greatest potential energy. 
E)  the product with the least potential energy. 
A)  the most stable product. 
B)  the product that can be formed in the fewest steps. 
C)  the product whose formation requires the smallest free energy of activation. 
D)  the product with the greatest potential energy. 
E)  the product with the least potential energy.

Question 8

Treatment of 4-methylcyclohexene with N-bromosuccinimide in CCl4 would yield mainly:

Accepted Answer

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

Question 9

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

Accepted Answer

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

Question 10

Estimate the stabilization energy for 1,3-butadiene 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
1
-126
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

Question 11

Which of the following dienes is a cumulated diene?

Accepted Answer

A)  CH2=CHCH2CH2CH=CH2 
B)  CH2=CHCH=CHCH2CH3 
C)  CH3CH=C=CHCH2CH3 
D)  CH3CH=CHCH=CHCH3 
E)  CH3CH=CHCH2CH=CH2 
A)  CH2=CHCH2CH2CH=CH2 
B)  CH2=CHCH=CHCH2CH3 
C)  CH3CH=C=CHCH2CH3 
D)  CH3CH=CHCH=CHCH3 
E)  CH3CH=CHCH2CH=CH2

Question 12

Steroids are naturally occurring polycyclic compounds classified as lipids.The Diels-
Alder reaction has been widely used in their preparation.Shown below is a precursor
molecule used in a total steroid synthesis.What combination of diene and dieneophile can
be used to prepare this compound through the use of a Diels-Alder cycloaddition reaction.

Accepted Answer

The answer of Steroids are naturally occurring polycyclic compounds classified...

Question 13

Which diene and dienophile would you choose to synthesize 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 14

Which carbon-carbon bond in the following compound would you expect to be longest?

Accepted Answer

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

Question 15

The first step in the total synthesis of synthetic cholesterol involves production of the
intermediate structure shown.Which combination of diene and dieneophile will result in
its preparation?

Accepted Answer

The answer of The first step in the total synthesis...

Question 16

An equilibrium-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 17

Which set of conditions does not result in allylic halogenation of an alkene?

Accepted Answer

A)  Cl2 at 400$\degree$C 
B)  Cl2 in CCl4 at 25$\degree$C 
C)  Cl2,ROOR,h$\nu$ 
D)  Br2 at low concentration in CCl4 
E)  N-Bromosuccinimide in CCl4,ROOR 
A)  Cl2 at 400$\degree$C 
B)  Cl2 in CCl4 at 25$\degree$C 
C)  Cl2,ROOR,h$\nu$ 
D)  Br2 at low concentration in CCl4 
E)  N-Bromosuccinimide in CCl4,ROOR

Question 18

Ignoring stereochemistry,the 1:1 reaction of bromine with 1,3-cyclohexadiene at 25$\degree$C in the dark and in the absence of peroxide forms which of these?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  Both I and II 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  Both I and II

Question 19

Which of these dienes is the most reactive in the Diels-Alder reaction?

Accepted Answer

A)  1,3-Butadiene 
B)  1,4-Pentadiene 
C)  2,3,-Dimethyl-1,3-butadiene 
D)  1,2-Butadiene 
E)  1,4-Cyclohexadiene 
A)  1,3-Butadiene 
B)  1,4-Pentadiene 
C)  2,3,-Dimethyl-1,3-butadiene 
D)  1,2-Butadiene 
E)  1,4-Cyclohexadiene

Question 20

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.

Exam 13: Conjugated Unsaturated Systems

The LUMO of 1,3-pentadiene has how many electrons in its ground state?

Which is the major product of the following reaction?

UV-vis spectroscopy can be used to indicate whether _________________ is present.

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

Treatment of 2-butene (cis or trans)with Cl2 at 400 °\degree° C would yield mainly:

How could the following synthesis be carried out?

A reaction under kinetic (or rate)control will yield predominantly:

Treatment of 4-methylcyclohexene with N-bromosuccinimide in CCl4 would yield mainly:

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

Estimate the stabilization energy for 1,3-butadiene 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 1 -126 1,3-Butadiene 2 -239 Trans-1,3-Pentadiene 2 -226

Which of the following dienes is a cumulated diene?

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

Which carbon-carbon bond in the following compound would you expect to be longest?

The first step in the total synthesis of synthetic cholesterol involves production of the intermediate structure shown.Which combination of diene and dieneophile will result in its preparation?

An equilibrium-controlled reaction will yield predominantly:

Which set of conditions does not result in allylic halogenation of an alkene?

Ignoring stereochemistry,the 1:1 reaction of bromine with 1,3-cyclohexadiene at 25 °\degree° C in the dark and in the absence of peroxide forms which of these?

Which of these dienes is the most reactive in the Diels-Alder reaction?

Which pair does not represent a pair of resonance structures?

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

Treatment of 2-butene (cis or trans)with Cl₂ at 400 $\degree$ C would yield mainly:

Treatment of 4-methylcyclohexene with N-bromosuccinimide in CCl₄ would yield mainly:

Estimate the stabilization energy for 1,3-butadiene 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 1 -126 1,3-Butadiene 2 -239 Trans-1,3-Pentadiene 2 -226