Question 1

How many nodes does the highest energy molecular orbital of 1,3,5,7-octatetraene have?

Accepted Answer

A) 4 
B) 5 
C) 6 
D) 8 
E) 10 
A) 4 
B) 5 
C) 6 
D) 8 
E) 10

Question 2

Give the product for the following reaction.

Accepted Answer

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

Question 3

Give the product for the following [1,5] sigmatropic rearrangement.

Accepted Answer

The answer of Give the product for the following [1,5]...

Question 4

Which of the following statements best describes what is meant by pericyclic reactions?

Accepted Answer

A) reactions in which a nucleophile reacts with an electrophile 
B) reactions in which an electrophile reacts with a nucleophile 
C) reactions in which a free radical reacts with another free radical 
D) oxidation-reduction reactions in which electrons are lost or gained 
E) reactions that occur as a result of a cyclic reorganization of electrons 
A) reactions in which a nucleophile reacts with an electrophile 
B) reactions in which an electrophile reacts with a nucleophile 
C) reactions in which a free radical reacts with another free radical 
D) oxidation-reduction reactions in which electrons are lost or gained 
E) reactions that occur as a result of a cyclic reorganization of electrons

Question 5

Is the thermal [4+2] cycloaddition between allylanion and ethylene an allowed one? To answer,draw the HOMO of allyl anion and the LUMO of ethylene,and comment on the symmetry match of the two.

Accepted Answer

The answer of Is the thermal [4+2] cycloaddition between allylanion...

Question 6

Describe a Cope rearrangement.

Accepted Answer

A) [3,3] sigmatropic rearrangement of a 1,5-diene 
B) [1,3] sigmatropic rearrangement of an alkene 
C) [3,3] sigmatropic rearrangement of an allyl vinyl ether 
D) [1,5] sigmatropic rearrangement of a 1,3-diene 
E) [2,3] sigmatropic rearrangement of an alkene 
A) [3,3] sigmatropic rearrangement of a 1,5-diene 
B) [1,3] sigmatropic rearrangement of an alkene 
C) [3,3] sigmatropic rearrangement of an allyl vinyl ether 
D) [1,5] sigmatropic rearrangement of a 1,3-diene 
E) [2,3] sigmatropic rearrangement of an alkene

Question 7

Which of the following statements about carbon migrations is correct?

Accepted Answer

A) Carbon migrations never occur by a sigmatropic rearrangement. 
B) Under thermal conditions,a [1,3] carbon migration that occurs suprafacially must also occur with inversion of configuration at the migrating carbon. 
C) Under thermal conditions,a [1,5] carbon migration that occurs suprafacially must also occur with inversion of configuration at the migrating carbon. 
D) Under thermal conditions,a carbon migration that occurs suprafacially must occur with inversion no matter the system's symmetry. 
E) B,C,and D 
A) Carbon migrations never occur by a sigmatropic rearrangement. 
B) Under thermal conditions,a [1,3] carbon migration that occurs suprafacially must also occur with inversion of configuration at the migrating carbon. 
C) Under thermal conditions,a [1,5] carbon migration that occurs suprafacially must also occur with inversion of configuration at the migrating carbon. 
D) Under thermal conditions,a carbon migration that occurs suprafacially must occur with inversion no matter the system's symmetry. 
E) B,C,and D

Question 8

Give the conditions for 1,7-hydrogen shifts.You may choose more than one answer.

Accepted Answer

A) suprafacial rearrangement 
B) antarafacial rearrangement 
C) thermal conditions 
D) photochemical conditions 
E) all of the above 
A) suprafacial rearrangement 
B) antarafacial rearrangement 
C) thermal conditions 
D) photochemical conditions 
E) all of the above

Question 9

Describe a sigmatropic rearrangement.

Accepted Answer

A) A sigma bond in the reactant has moved to a different location in the product,and the pi bonds have rearranged. 
B) The product contains a new ring,with two less sigma bonds,and two more pi bonds than the starting material. 
C) The product contains a new ring,with two more sigma bonds,and two less pi bonds than the starting material. 
D) The product contains a new ring,with one less sigma bond,and one more pi bond than the starting material. 
E) The product contains a new ring,with one more sigma bond,and one less pi bond than the starting material. 
A) A sigma bond in the reactant has moved to a different location in the product,and the pi bonds have rearranged. 
B) The product contains a new ring,with two less sigma bonds,and two more pi bonds than the starting material. 
C) The product contains a new ring,with two more sigma bonds,and two less pi bonds than the starting material. 
D) The product contains a new ring,with one less sigma bond,and one more pi bond than the starting material. 
E) The product contains a new ring,with one more sigma bond,and one less pi bond than the starting material.

Question 10

What is the product of the following reaction?

Accepted Answer

The answer of What is the product of the following...

Question 11

How many molecular orbitals are produced from the overlap of four p atomic orbitals?

Accepted Answer

A) 2 
B) 8 
C) 4 
D) 16 
E) 1 
A) 2 
B) 8 
C) 4 
D) 16 
E) 1

Question 12

Under what conditions would a 1,5-hydrogen shift occur in a sigmatropic rearrangement?

Accepted Answer

A) thermal conditions 
B) photochemical conditions 
C) suprafacial pathway 
D) A and C 
E) B and C 
A) thermal conditions 
B) photochemical conditions 
C) suprafacial pathway 
D) A and C 
E) B and C

Question 13

Under photochemical conditions,is an [2+2] cycloaddition suprafacial or antarafacial?

Accepted Answer

The answer of Under photochemical conditions,is an [2+2] cycloaddition suprafacial...

Question 14

Which of the following sets of atomic orbitals form an asymmetric molecular orbital?

Accepted Answer

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

Question 15

What is the product of the following 1,7-hydrogen shift?

Accepted Answer

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

Question 16

When an allyl anion undergoes a cycloaddition under thermal conditions with ethylene (bonds forming at the ends of the π-systems),the cycloaddition is described as

Accepted Answer

A) [2+2] and suprafacial. 
B) [2+4] and suprafacial. 
C) [2+2] and antarafacial. 
D) [2+4] and antarafacial. 
E) [2+3] and antarafacial. 
A) [2+2] and suprafacial. 
B) [2+4] and suprafacial. 
C) [2+2] and antarafacial. 
D) [2+4] and antarafacial. 
E) [2+3] and antarafacial.

Question 17

How many electrons are present in the nonbonding π molecular orbital of the allyl anion?

Accepted Answer

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

Question 18

Under photochemical conditions,(2E,4Z)-hexadiene undergoes a ________ ring closure to yield ________.

Accepted Answer

A) conrotatory,cis-3,4-dimethylcyclobutene 
B) conrotatory,trans-3,4-dimethylcyclobutene 
C) disrotatory,cis-3,4-dimethylcyclobutene 
D) disrotatory,trans-3,4-dimethylcyclobutene 
A) conrotatory,cis-3,4-dimethylcyclobutene 
B) conrotatory,trans-3,4-dimethylcyclobutene 
C) disrotatory,cis-3,4-dimethylcyclobutene 
D) disrotatory,trans-3,4-dimethylcyclobutene

Question 19

Give the product(s)for the following reaction.You may choose more than one answer.

Accepted Answer

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

Question 20

Indicate whether each of the following reactions is an electrocyclic reaction,a cycloaddition reaction,or a sigmatropic rearrangement.

Accepted Answer

a)Is an electrocycli

Exam 28: Pericyclic Reactions

How many nodes does the highest energy molecular orbital of 1,3,5,7-octatetraene have?

Give the product for the following reaction.

Give the product for the following [1,5] sigmatropic rearrangement.

Which of the following statements best describes what is meant by pericyclic reactions?

Is the thermal [4+2] cycloaddition between allylanion and ethylene an allowed one? To answer,draw the HOMO of allyl anion and the LUMO of ethylene,and comment on the symmetry match of the two.

Describe a Cope rearrangement.

Which of the following statements about carbon migrations is correct?

Give the conditions for 1,7-hydrogen shifts.You may choose more than one answer.

Describe a sigmatropic rearrangement.

What is the product of the following reaction?

How many molecular orbitals are produced from the overlap of four p atomic orbitals?

Under what conditions would a 1,5-hydrogen shift occur in a sigmatropic rearrangement?

Under photochemical conditions,is an [2+2] cycloaddition suprafacial or antarafacial?

Which of the following sets of atomic orbitals form an asymmetric molecular orbital?

What is the product of the following 1,7-hydrogen shift?

When an allyl anion undergoes a cycloaddition under thermal conditions with ethylene (bonds forming at the ends of the π-systems),the cycloaddition is described as

How many electrons are present in the nonbonding π molecular orbital of the allyl anion?

Under photochemical conditions,(2E,4Z)-hexadiene undergoes a ________ ring closure to yield ________.

Give the product(s)for the following reaction.You may choose more than one answer.

Indicate whether each of the following reactions is an electrocyclic reaction,a cycloaddition reaction,or a sigmatropic rearrangement.

Remembering General Chemistry: Electronic Structure and Bonding

Acids and Bases: Central to Understanding Organic Chemistry

An Introduction to Organic Compounds: Nomenclature, physical Properties, and Structure

Isomers: the Arrangement of Atoms in Space

Alkenes: Structure,nomenclature,and an Introduction to Reactivity - Thermodynamics and Kinetics

The Reactions of Alkenes - the Stereochemistry of Addition Reactions

The Reactions of Alkynes - Introduction to Multistep Synthesis

Delocalized Electrons: Their Effect on Stability, pka, and the Products of a Reaction - Aromaticity and Electronic Effects: an Introduction to the Reactions of Benzene

Substitution and Elimination Reactions of Alkyl Halides

Reactions of Alcohols, ethers, epoxides, amines and Sulfur-Containing Compounds

Organometallic Compounds

Radicals

Mass Spectrometry,infrared Spectroscopy,and Uvvis Spectroscopy

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones

Reactions at the Α-Carbon

Reactions of Benzene and Substituted Benzenes

More About Amines - Reactions of Heterocylic Compounds

The Organic Chemistry of Carbohydrates

Amino Acids,peptides,and Proteins

Catalysis in Organic Reactions and in Enzymatic Reactions

The Organic Chemistry of the Coenzymes, compounds Derived From Vitamins

The Organic Chemistry of the Metabolic Pathways

The Organic Chemistry of Lipids

The Chemistry of the Nucleic Acids

Synthetic Polymers

Filters

Under photochemical conditions,(2E,4Z)-hexadiene undergoes a ring closure to yield .