Question 1

Draw the structural formula for (R)-5-bromo-2,5-dimethyl-1,3-cyclopentadiene,clearly indicating stereochemical details.

Accepted Answer

The answer of Draw the structural formula for (R)-5-bromo-2,5-dimethyl-1,3-cyclopentadiene,clearly indicating...

Question 2

The hydrogen atom on a carbon that is part of a double bond is called a ___ hydrogen.

Accepted Answer

vinyl or vinylic

Question 3

Which of these symbols is used in connection with the intensity of absorption in the UV-visible region?

Accepted Answer

A) "$\infty$" 
B) "$v$" 
C) "$\varepsilon$" 
D) "$\lambda$" 
E) "$\theta$" 
A) "$\infty$" 
B) "$v$" 
C) "$\varepsilon$" 
D) "$\lambda$" 
E) "$\theta$" C

Question 4

Which of the following pairs of compounds could be used as the basis for a Diels-Alder synthesis of the compound shown below?

Accepted Answer

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

Question 5

Which pair does not represent a pair of resonance structures?

Accepted Answer

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

Question 6

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

@#IMG-DLM& Topic Die

Question 7

The LUMO of the allylic radical 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 8

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 9

There are three types of polyenes (molecules containing two or more double bonds).They are: ___.

Accepted Answer

conjugated

Question 10

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 11

Which reaction would produce the following compound?

Accepted Answer

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

Question 12

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 13

Which carbocation 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

1,3-Butadiene has how many electrons in its ground state antibonding $\pi$ molecular orbitals?

Accepted Answer

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

Question 15

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 16

The accompanying diagram,which describes the fate of the intermediate in a reversible reaction,implies that:

Accepted Answer

A) the less stable product forms more rapidly. 
B) the more stable product forms more rapidly. 
C) product B will predominate at equilibrium. 
D) the intermediate has a short lifetime. 
E) No conclusions can be drawn as to either reaction rate or product stability. 
A) the less stable product forms more rapidly. 
B) the more stable product forms more rapidly. 
C) product B will predominate at equilibrium. 
D) the intermediate has a short lifetime. 
E) No conclusions can be drawn as to either reaction rate or product stability.

Question 17

The accompanying diagram,which describes the fate of the intermediate in a reversible reaction,implies that:

Accepted Answer

A) the less stable product forms more rapidly. 
B) the more stable product forms more rapidly. 
C) product B will predominate at equilibrium. 
D) the intermediate has a short lifetime. 
E) No conclusions can be drawn as to either reaction rate or product stability. 
A) the less stable product forms more rapidly. 
B) the more stable product forms more rapidly. 
C) product B will predominate at equilibrium. 
D) the intermediate has a short lifetime. 
E) No conclusions can be drawn as to either reaction rate or product stability.

Question 18

The allyl radical 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 19

Which would be the best synthesis of the following compound?

Accepted Answer

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

Question 20

The substituent R on the bicyclic compound shown is considered to be?

Accepted Answer

A) axial 
B) equatorial 
C) endo 
D) exo 
E) trans 
A) axial 
B) equatorial 
C) endo 
D) exo 
E) trans

Exam 13: Conjugated Unsaturated Systems

Draw the structural formula for (R)-5-bromo-2,5-dimethyl-1,3-cyclopentadiene,clearly indicating stereochemical details.

The hydrogen atom on a carbon that is part of a double bond is called a ___ hydrogen.

Which of these symbols is used in connection with the intensity of absorption in the UV-visible region?

Which of the following pairs of compounds could be used as the basis for a Diels-Alder synthesis of the compound shown below?

Which pair does not represent a pair of resonance structures?

The LUMO of the allylic radical has how many electrons in its ground state?

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

There are three types of polyenes (molecules containing two or more double bonds).They are: ___.

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

Which reaction would produce the following compound?

A thermodynamically-controlled reaction will yield predominantly:

Which carbocation would be least stable?

1,3-Butadiene has how many electrons in its ground state antibonding π\piπ molecular orbitals?

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

The accompanying diagram,which describes the fate of the intermediate in a reversible reaction,implies that:

The accompanying diagram,which describes the fate of the intermediate in a reversible reaction,implies that:

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

Which would be the best synthesis of the following compound?

The substituent R on the bicyclic compound shown is considered to be?

The Basics

Families of Carbon

Acids and Bases

Nomenclature and Conformations of Alkanes and Cycloalkanes

Stereochemistry

Nucleophilic Reactions

Alkenes and Alkynes I

Alkenes and Alkynes II

Nuclear Magnetic Resonance and Mass Spectrometry

Radical Reactions

Alcohols and Ethers

Alcohols From Carbonyl Compounds

Aromatic Compounds

Reactions of Aromatic Compounds

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Reactions at the Α Carbon of Carbonyl Compounds

Condensation and Conjugate Addition Reactions of Carbonyl Compounds

Amines

Transition Metal Complexes

Carbohydrates

Lipids

Amino Acids and Proteins

Nucleic Acids and Protein Synthesis

Filters

1,3-Butadiene has how many electrons in its ground state antibonding $\pi$ molecular orbitals?

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

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