Question 1

The photochemical cycloaddition of the structure below is related to DNA mutations causing skin cancer.Draw the structure of this dimer.Atoms other than carbon and hydrogen are labeled.

Accepted Answer

[2+2] cycloaddition occurs due to photochemical conditions.

Question 2

Exhibit 30-3
To answer the following question(s),consider the reaction below: 
-Refer to Exhibit 30-3.Explain the stereochemistry of compound Y.

Accepted Answer

Thermal electrocyclic opening of the cis...

Question 3

Which of the following is not an electrocyclic reaction?

Accepted Answer

A)   
B)   
C)   
D)   
E)  All are electrocyclic reactions.F) B) and D)
G) A) and D)

Question 4

Exhibit 30-4
Consider the reaction below to answer the following question(s) : 
-Refer to Exhibit 30-4.How many pairs of electrons are involved in this pericyclic reaction?

Accepted Answer

A)  two
B)  four
C)  eight
D)  sixteenE) None of the above
F) A) and D)

Question 5

For an even number of electron pairs (double bonds) ,which of the following rules is correct?:

Accepted Answer

A)  thermal conditions - controtatory,photochemical conditions - disrotatory
B)  thermal conditions - disrotatory,photochemical conditions - conrotatoryC) A) and B)
D) undefined

Question 6

The mnemonic phrase "The Electrons Circle Around",TECA,assists in predicting stereochemistry of pericyclic reactions.Describe application of this mnemonic.

Accepted Answer

The mnemonic TECA assists us in remember...

Question 7

Exhibit 30-3
To answer the following question(s),consider the reaction below: 
-Refer to Exhibit 30-3.Two pericyclic reactions are involved in this synthesis of compound Y.Draw the structure of intermediate X and name it using IUPAC nomenclature.

Accepted Answer

The answer of Exhibit 30-3
To answer the following question(s),consider the...

Question 8

Exhibit 30-4
Consider the reaction below to answer the following question(s): 
-Refer to Exhibit 30-4.Explain the stereochemistry of this reaction.

Accepted Answer

The reaction of heptafulvene w...

Question 9

Exhibit 30-5
To answer the following question(s),consider the reaction below: 
-Refer to Exhibit 30-5.Propose a mechanism for the reaction that fully accounts for the formation of both products.

Accepted Answer

<img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"> This reaction occurs with suprafacial s...

Question 10

Exhibit 30-6
Consider the reaction sequence below to answer the following question(s) : 
-Refer to Exhibit 30-6.Step 2 is an example of:

Accepted Answer

A)  an electrocyclic reaction.
B)  a cycloaddition reaction.
C)  a sigmatropic rearrangement.
D)  a reverse cycloaddition reaction.E) A) and C)
F) C) and D)

Question 11

Predict the product of the following reaction.

Accepted Answer

The answer of Predict the product of the following reaction....

Question 12

Exhibit 30-7
Consider the Sommelet-Hauser rearrangement below to answer the following question(s) : 
-Refer to Exhibit 30-7.The Sommelet-Hauser rearrangement is an example of a [2,3] sigmatropic rearrangement.How many pairs of electrons are involved in this reaction?

Accepted Answer

A)  two
B)  three
C)  four
D)  fiveE) None of the above
F) B) and C) B

Question 13

Exhibit 30-6
Consider the reaction sequence below to answer the following question(s) : 
-Refer to Exhibit 30-6.Step 1 is an example of:

Accepted Answer

A)  an electrocyclic reaction
B)  a cycloaddition reaction
C)  a sigmatropic rearrangement
D)  a reverse cycloaddition reactionE) B) and D)
F) B) and C)

Question 14

Exhibit 30-6
Consider the reaction sequence below to answer the following question(s): 
-Refer to Exhibit 30-6.Show how C is formed from B.

Accepted Answer

The answer of Exhibit 30-6
Consider the reaction sequence below to...

Question 15

Under thermal conditions,the following substance will undergo:

Accepted Answer

A)  disrotatory cyclization.
B)  conrotatory cyclization.
C)  no reaction.D) A) and B)
E) A) and C) A

Question 16

In which type of pericyclic reaction is a σ bond broken and a new σ bond formed?

Accepted Answer

A)  cycloaddition
B)  photochemical electrocyclic
C)  thermal electrocyclic
D)  sigmatropic rearrangement.
E)  all of the aboveF) A) and B)
G) B) and D)

Question 17

Exhibit 30-2
Consider the reaction below to answer the following question(s): 
-Refer to Exhibit 30-2.Under what conditions,thermal or photochemical,would you carry out this reaction? Explain.

Accepted Answer

For a disrotatory cyclization to occur t...

Question 18

Exhibit 30-2
Consider the reaction below to answer the following question(s): 
-Refer to Exhibit 30-2.Has this reaction taken place in a conrotatory manner or in a disrotatory manner?

Accepted Answer

In order for the hyd...

Question 19

Exhibit 30-9
Vitamin D3,cholecalciferol,is synthesized under the skin by the photochemical pericyclic process shown below.Answer the following question(s)  about these reactions. 3,cholecalciferol,is synthesized under the skin by the photochemical pericyclic process shown below.Answer the following question(s)  about these reactions.   -Refer to Exhibit 30-9.The first step in this process is a(n) : A) sigmatropic rearrangement B) cycloaddition reaction C) annulation reaction D) electrocyclic reaction" class="answers-bank-image d-inline" rel="preload" >
-Refer to Exhibit 30-9.The first step in this process is a(n) :

Accepted Answer

A)  sigmatropic rearrangement
B)  cycloaddition reaction
C)  annulation reaction
D)  electrocyclic reactionE) C) and D)
F) A) and C)

Question 20

Under photochemical conditions,the following substance will undergo:

Accepted Answer

A)  disrotatory cyclization.
B)  conrotatory cyclization.
C)  no reaction.D) A) and C)
E) A) and B)

Exam 30: Orbitals and Organic Chemistry: Pericyclic Reactions

The photochemical cycloaddition of the structure below is related to DNA mutations causing skin cancer.Draw the structure of this dimer.Atoms other than carbon and hydrogen are labeled.

Correct Answerverified[2+2] cycloaddition occurs due to photochemical conditions. 11eab917_14d8_7e55_99e6_a5ba12e5161e_TB4944_00

Exhibit 30-3 To answer the following question(s),consider the reaction below: -Refer to Exhibit 30-3.Explain the stereochemistry of compound Y.

Correct AnswerverifiedThermal electrocyclic opening of the cis...View AnswerShow Answer

Which of the following is not an electrocyclic reaction?

Correct AnswerverifiedShow Answer

Exhibit 30-4 Consider the reaction below to answer the following question(s) : -Refer to Exhibit 30-4.How many pairs of electrons are involved in this pericyclic reaction?

Correct AnswerverifiedShow Answer

For an even number of electron pairs (double bonds) ,which of the following rules is correct?:

Correct AnswerverifiedShow Answer

The mnemonic phrase "The Electrons Circle Around",TECA,assists in predicting stereochemistry of pericyclic reactions.Describe application of this mnemonic.

Correct AnswerverifiedThe mnemonic TECA assists us in remember...View AnswerShow Answer

Exhibit 30-3 To answer the following question(s),consider the reaction below: -Refer to Exhibit 30-3.Two pericyclic reactions are involved in this synthesis of compound Y.Draw the structure of intermediate X and name it using IUPAC nomenclature.

Correct AnswerverifiedShow Answer

Exhibit 30-4 Consider the reaction below to answer the following question(s): -Refer to Exhibit 30-4.Explain the stereochemistry of this reaction.

Correct AnswerverifiedThe reaction of heptafulvene w...View AnswerShow Answer

Exhibit 30-5 To answer the following question(s),consider the reaction below: -Refer to Exhibit 30-5.Propose a mechanism for the reaction that fully accounts for the formation of both products.

Correct Answerverified This reaction occurs with suprafacial s...View AnswerShow Answer

Exhibit 30-6 Consider the reaction sequence below to answer the following question(s) : -Refer to Exhibit 30-6.Step 2 is an example of:

Correct AnswerverifiedShow Answer

Predict the product of the following reaction.

Correct AnswerverifiedShow Answer

Exhibit 30-7 Consider the Sommelet-Hauser rearrangement below to answer the following question(s) : -Refer to Exhibit 30-7.The Sommelet-Hauser rearrangement is an example of a [2,3] sigmatropic rearrangement.How many pairs of electrons are involved in this reaction?

Correct AnswerverifiedB

Exhibit 30-6 Consider the reaction sequence below to answer the following question(s) : -Refer to Exhibit 30-6.Step 1 is an example of:

Correct AnswerverifiedShow Answer

Exhibit 30-6 Consider the reaction sequence below to answer the following question(s): -Refer to Exhibit 30-6.Show how C is formed from B.

Correct AnswerverifiedShow Answer

Under thermal conditions,the following substance will undergo:

Correct AnswerverifiedA

In which type of pericyclic reaction is a σ bond broken and a new σ bond formed?

Correct AnswerverifiedShow Answer

Exhibit 30-2 Consider the reaction below to answer the following question(s): -Refer to Exhibit 30-2.Under what conditions,thermal or photochemical,would you carry out this reaction? Explain.

Correct AnswerverifiedFor a disrotatory cyclization to occur t...View AnswerShow Answer

Exhibit 30-2 Consider the reaction below to answer the following question(s): -Refer to Exhibit 30-2.Has this reaction taken place in a conrotatory manner or in a disrotatory manner?

Correct AnswerverifiedIn order for the hyd...View AnswerShow Answer

Exhibit 30-9 Vitamin D3,cholecalciferol,is synthesized under the skin by the photochemical pericyclic process shown below.Answer the following question(s) about these reactions. -Refer to Exhibit 30-9.The first step in this process is a(n) :

Correct AnswerverifiedShow Answer

Under photochemical conditions,the following substance will undergo:

Correct AnswerverifiedShow Answer

Correct Answer
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[2+2] cycloaddition occurs due to photochemical conditions. 11eab917_14d8_7e55_99e6_a5ba12e5161e_TB4944_00

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Thermal electrocyclic opening of the cis...
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The mnemonic TECA assists us in remember...
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The reaction of heptafulvene w...
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This reaction occurs with suprafacial s...
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B

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A

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For a disrotatory cyclization to occur t...
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In order for the hyd...
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Exhibit 30-9 Vitamin D₃,cholecalciferol,is synthesized under the skin by the photochemical pericyclic process shown below.Answer the following question(s) about these reactions. -Refer to Exhibit 30-9.The first step in this process is a(n) :

Correct Answer
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