Question 1

What characterizes a pericyclic reaction?

Accepted Answer

Pericyclic reactions involve c...

Question 2

Provide the structure of the major organic product in the following reaction.

Accepted Answer

The answer of Provide the structure of the major organic...

Question 3

Draw the major organic product that results from the intramolecular Diels-Alder reaction.

Accepted Answer

The answer of Draw the major organic product that results...

Question 4

Which of the following terms best describes a Diels-Alder reaction?

Accepted Answer

A)   a [4+2] cycloaddition
B)   a [2+2] cycloaddition
C)   a sigmatropic rearrangement
D)   a 1,3-dipolar cycloaddition
E)   a substitution reactionF) A) and B)
G) A) and E)

Question 5

Which of the following compounds is the most reactive dienophile in a Diels-Alder reaction with 1,3-butadiene?

Accepted Answer

A)   CH2  2     CHOCH3 
B)   CH2     CHCHO 
C)   CH3CH   CHCH3 
D)   (CH3) 2C   CH2 
E)   CH2     CH2" class="answers-bank-image d-inline" rel="preload" >CHOCH3
B)   CH2  2     CHOCH3 
B)   CH2     CHCHO 
C)   CH3CH   CHCH3 
D)   (CH3) 2C   CH2 
E)   CH2     CH2" class="answers-bank-image d-inline" rel="preload" >CHCHO
C)   CH3CH 2     CHOCH3 
B)   CH2     CHCHO 
C)   CH3CH   CHCH3 
D)   (CH3) 2C   CH2 
E)   CH2     CH2" class="answers-bank-image d-inline" rel="preload" > CHCH3
D)   (CH3) 2C 2     CHOCH3 
B)   CH2     CHCHO 
C)   CH3CH   CHCH3 
D)   (CH3) 2C   CH2 
E)   CH2     CH2" class="answers-bank-image d-inline" rel="preload" > CH2
E)   CH2  2     CHOCH3 
B)   CH2     CHCHO 
C)   CH3CH   CHCH3 
D)   (CH3) 2C   CH2 
E)   CH2     CH2" class="answers-bank-image d-inline" rel="preload" >CH2F) All of the above
G) None of the above

Question 6

The following [3+2] cycloaddition was reported in Organic Letters, 2011, 402. Predict whether the reaction would be thermally or photochemically promoted. Justify your answer by showing overlap of the correct molecular orbitals. Assume the alkene is the electrophile.

Accepted Answer

The answer of The following [3+2] cycloaddition was reported in...

Question 7

What descriptive term is applied to the type of diene represented by 1,5-octadiene?

Accepted Answer

A)   conjugated diene
B)   cumulated diene
C)   isolated diene
D)   alkynyl diene
E)   none of the aboveF) B) and C)
G) A) and D)

Question 8

Dicylopentadiene results when cyclopentadiene reacts with itself in a Diels-Alder reaction. Provide the structure of dicyclopentadiene. Pay particular attention to stereochemical detail.

Accepted Answer

The answer of Dicylopentadiene results when cyclopentadiene reacts with itself...

Question 9

For what does the acronym HOMO stand?

Accepted Answer

highest oc...

Question 10

Using resonance structures, explain the regiochemistry observed in this reaction:

Accepted Answer

The answer of Using resonance structures, explain the regiochemistry observed...

Question 11

How many nodes, other than the node coincident with the molecular plane, are present in the LUMO of 1,3,5-hexatriene?

Accepted Answer

A)   1
B)   2
C)   3
D)   4
E)   5F) B) and D)
G) C) and D)

Question 12

Assuming kinetic conditions, draw the major product of the reaction below. Include correct stereochemistry.

Accepted Answer

The answer of Assuming kinetic conditions, draw the major product...

Question 13

Draw the most stable conformation of (2Z,4E)-2,4-hexadiene.

Accepted Answer

The answer of Draw the most stable conformation of (2Z,4E)-2,4-hexadiene....

Question 14

Provide the structure of the major organic product in the following reaction.

Accepted Answer

The answer of Provide the structure of the major organic...

Question 15

How many nodes, other than the node coincident with the molecular plane, are present in the HOMO of 1,3,5-hexatriene?

Accepted Answer

A)   1
B)   2
C)   3
D)   4
E)   5F) A) and C)
G) A) and E)

Question 16

What is the major organic product which results when cycloheptene is irradiated in the presence of N-bromosuccinimide?

Accepted Answer

A)   1-bromocycloheptene
B)   2-bromocycloheptene
C)   1,2-dibromocycloheptane
D)   3-bromocycloheptene
E)   4-bromocyclohepteneF) B) and D)
G) B) and E)

Question 17

When 3-bromo-1-methylcyclohexene is heated in a good ionizing solvent, reactions occur through a carbocation intermediate. Draw all reasonable resonance contributors of this cation and indicate which is the major contributor.

Accepted Answer

The answer of When 3-bromo-1-methylcyclohexene is heated in a good...

Question 18

Which has a λmax in its UV spectrum at a longer wavelength, 2,4-hexadiene, 1,4-hexadiene, or 1,5-hexadiene?

Accepted Answer

Question 19

Give a representation of the highest occupied π MO of 1,3-butadiene in its ground state.

Accepted Answer

The answer of Give a representation of the highest occupied...

Question 20

Which sequence correctly ranks the following conjugated systems in order of increasing UV λmax absorption values? max absorption values?   A)  1

Accepted Answer

A)   1 
B)   2 
C)   2 
D)   3 
E)   3 < 2 < 1F) A) and D)
G) A) and C)

Exam 15: Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Which of the following terms best describes a Diels-Alder reaction?

Correct AnswerverifiedShow Answer

Provide the structure of the major organic product in the following reaction.

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For what does the acronym HOMO stand?

Correct Answerverifiedhighest oc...View AnswerShow Answer

Using resonance structures, explain the regiochemistry observed in this reaction:

Correct AnswerverifiedShow Answer

Assuming kinetic conditions, draw the major product of the reaction below. Include correct stereochemistry.

Correct AnswerverifiedShow Answer

The following [3+2] cycloaddition was reported in Organic Letters, 2011, 402. Predict whether the reaction would be thermally or photochemically promoted. Justify your answer by showing overlap of the correct molecular orbitals. Assume the alkene is the electrophile.

Correct AnswerverifiedShow Answer

Draw the most stable conformation of (2Z,4E)-2,4-hexadiene.

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Provide the structure of the major organic product in the following reaction.

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What characterizes a pericyclic reaction?

Correct AnswerverifiedPericyclic reactions involve c...View AnswerShow Answer

How many nodes, other than the node coincident with the molecular plane, are present in the LUMO of 1,3,5-hexatriene?

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Which has a λmax in its UV spectrum at a longer wavelength, 2,4-hexadiene, 1,4-hexadiene, or 1,5-hexadiene?

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Give a representation of the highest occupied π MO of 1,3-butadiene in its ground state.

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How many nodes, other than the node coincident with the molecular plane, are present in the HOMO of 1,3,5-hexatriene?

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Which of the following compounds is the most reactive dienophile in a Diels-Alder reaction with 1,3-butadiene?

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What is the major organic product which results when cycloheptene is irradiated in the presence of N-bromosuccinimide?

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When 3-bromo-1-methylcyclohexene is heated in a good ionizing solvent, reactions occur through a carbocation intermediate. Draw all reasonable resonance contributors of this cation and indicate which is the major contributor.

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Dicylopentadiene results when cyclopentadiene reacts with itself in a Diels-Alder reaction. Provide the structure of dicyclopentadiene. Pay particular attention to stereochemical detail.

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What descriptive term is applied to the type of diene represented by 1,5-octadiene?

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Which sequence correctly ranks the following conjugated systems in order of increasing UV λmax absorption values?

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Draw the major organic product that results from the intramolecular Diels-Alder reaction.

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highest oc...
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Pericyclic reactions involve c...
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Which has a λ_max in its UV spectrum at a longer wavelength, 2,4-hexadiene, 1,4-hexadiene, or 1,5-hexadiene?

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Which sequence correctly ranks the following conjugated systems in order of increasing UV λ_max absorption values?

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Correct Answer
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