Question 1

Which of the following is not a feature of the Diels-Alder reaction?

Accepted Answer

A)  They are initiated by peroxides.
B)  They form new six-membered rings.
C)  Three π bonds break.
D)  They are concerted.E) B) and D)
F) A) and D)

Question 2

Which of the following electronic transitions is common in the UV spectrum of 1,3-butadiene?

Accepted Answer

A)  s®p
B)  s®p*
C)  n ®p*
D)  p®p*E) None of the above
F) C) and D)

Question 3

Which of the following is (are) conjugated dienes?

Accepted Answer

A)  Only I
B)  Only II
C)  Only I and II
D)  I,II,and IIIE) A) and B)
F) None of the above

Question 4

What is the major organic product of the following reaction?

Accepted Answer

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

Question 5

Which of the following is the most reactive diene in a Diels-Alder reaction?

Accepted Answer

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

Question 6

Rank the following compounds in order of increasing stability,putting the least stable first.

Accepted Answer

A)  I 
B)  III 
C)  II 
D)  III < I < IIE) A) and B)
F) A) and C)

Question 7

What is the major product of the following reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) None of the above
F) A) and B)

Question 8

Which triene has the largest heat of hydrogenation?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) All of the above
F) None of the above D

Question 9

Which of the following statements about the Diels-Alder reaction is true?

Accepted Answer

A)  The diene can react only when it adopts the s-trans conformation.
B)  Electron-withdrawing substituents in the diene increase reaction rate.
C)  Electron-donating substituents in the dienophile increase the reaction rate.
D)  The stereochemistry of the dienophile is retained in the product.E) C) and D)
F) None of the above

Question 10

What is (are) the major product(s) of the following reaction?

Accepted Answer

A)  Only I
B)  Only II
C)  Only I and II
D)  I,II,and IIIE) A) and B)
F) B) and C)

Question 11

Which of the following is the least reactive diene in a Diels-Alder reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) All of the above
F) A) and D) D

Question 12

What is the kinetic product obtained from the addition of 1 equivalent of HBr to 1,3-butadiene?

Accepted Answer

A)  3-Bromo-1-butene
B)  1-Bromo-2-butene
C)  2-Bromo-2-butene
D)  2-Bromo-1-buteneE) B) and C)
F) A) and D)

Question 13

Which of the following is an example of a bridged bicyclic system?

Accepted Answer

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

Question 14

Rank the following dienophile in order of increasing reactivity in a Diels-Alder reaction,listing the least reactive first.

Accepted Answer

A)  I 
B)  III 
C)  II 
D)  III < II < IE) A) and D)
F) A) and C)

Question 15

Which of the following is the appropriate term for the mechanism of the addition of HBr to 1,3-dienes?

Accepted Answer

A)  Nucleophilic addition
B)  Electrophilic addition
C)  Free radical addition
D)  Conjugate additionE) A) and B)
F) A) and D)

Question 16

Which of the following is a major resonance contributor to the first structure?

Accepted Answer

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

Question 17

Which triene absorbs the longest wavelength of UV light?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) None of the above
F) A) and B) A

Question 18

What diene and dienophile are used in a Diels-Alder reaction to prepare the following compound?

Accepted Answer

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

Question 19

Which of the following is not a product obtained from the addition of 1 equivalent of HBr to (E) -1,3-pentadiene?

Accepted Answer

A)  (
E)  -4-Bromo-2-pentene
B)  (
E)  -1-Bromo-2-pentene
C)  3-Bromo-1-pentene
D)  (
E)  -3-Bromo-2-penteneE) B) and C)
F) B) and D)

Question 20

What is the major product of the following reaction?

Accepted Answer

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

Exam 14: Conjugation, resonance, and Dienes

Which of the following is not a feature of the Diels-Alder reaction?

Correct AnswerverifiedShow Answer

Which of the following electronic transitions is common in the UV spectrum of 1,3-butadiene?

Correct AnswerverifiedShow Answer

Which of the following is (are) conjugated dienes?

Correct AnswerverifiedShow Answer

What is the major organic product of the following reaction?

Correct AnswerverifiedShow Answer

Which of the following is the most reactive diene in a Diels-Alder reaction?

Correct AnswerverifiedShow Answer

Rank the following compounds in order of increasing stability,putting the least stable first.

Correct AnswerverifiedShow Answer

What is the major product of the following reaction?

Correct AnswerverifiedShow Answer

Which triene has the largest heat of hydrogenation?

Correct AnswerverifiedD

Which of the following statements about the Diels-Alder reaction is true?

Correct AnswerverifiedShow Answer

What is (are) the major product(s) of the following reaction?

Correct AnswerverifiedShow Answer

Which of the following is the least reactive diene in a Diels-Alder reaction?

Correct AnswerverifiedD

What is the kinetic product obtained from the addition of 1 equivalent of HBr to 1,3-butadiene?

Correct AnswerverifiedShow Answer

Which of the following is an example of a bridged bicyclic system?

Correct AnswerverifiedShow Answer

Rank the following dienophile in order of increasing reactivity in a Diels-Alder reaction,listing the least reactive first.

Correct AnswerverifiedShow Answer

Which of the following is the appropriate term for the mechanism of the addition of HBr to 1,3-dienes?

Correct AnswerverifiedShow Answer

Which of the following is a major resonance contributor to the first structure?

Correct AnswerverifiedShow Answer

Which triene absorbs the longest wavelength of UV light?

Correct AnswerverifiedA

What diene and dienophile are used in a Diels-Alder reaction to prepare the following compound?

Correct AnswerverifiedShow Answer

Which of the following is not a product obtained from the addition of 1 equivalent of HBr to (E) -1,3-pentadiene?

Correct AnswerverifiedShow Answer

What is the major product of the following reaction?

Correct AnswerverifiedShow Answer

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